Hemp: A New Crop with New Uses for North America*

Hemp refers primarily to Cannabis sativa L. (Cannabaceae),
although the term has been applied to dozens of species representing at least
22 genera, often prominent fiber crops. For examples, Manila hemp (abaca) is
Musa textilis Née, sisal hemp is Agave sisalina Perrine,
and sunn hemp is Crotolaria juncea L. Especially confusing is the phrase
Indian hemp, which has been used both for narcotic Asian land races
of C. sativa (so-called C. indica Lamarck of India) and Apocynum
cannabinum L., which was used by North American Indians as a fiber plant.
Cannabis sativa is a multi-purpose plant that has been domesticated for
bast (phloem) fiber in the stem, a multi-purpose fixed oil in the seeds
(achenes), and an intoxicating resin secreted by epidermal glands. The common
names hemp and marijuana (much less frequently spelled marihuana) have been
applied loosely to all three forms, although historically hemp has been used
primarily for the fiber cultigen and its fiber preparations, and marijuana for
the drug cultigen and its drug preparations. The current hemp industry is making
great efforts to point out that hemp is not marijuana. Italicized,
Cannabis refers to the biological name of the plant (only one species
of this genus is commonly recognized, C. sativa L.). Non-italicized,
cannabis is a generic abstraction, widely used as a noun and adjective,
and commonly (often loosely) used both for cannabis plants and/or any or all
of the intoxicant preparations made from them.

Probably indigenous to temperate Asia, C. sativa is the most widely
cited example of a camp follower. It was pre-adapted to thrive in
the manured soils around mans early settlements, which quickly led to
its domestication (Schultes 1970). Hemp was harvested by the Chinese 8500 years
ago (Schultes and Hofmann 1980). For most of its history, C. sativa was
most valued as a fiber source, considerably less so as an intoxicant, and only
to a limited extent as an oilseed crop. Hemp is one of the oldest sources of
textile fiber, with extant remains of hempen cloth trailing back 6 millennia.
Hemp grown for fiber was introduced to western Asia and Egypt, and subsequently
to Europe somewhere between 1000 and 2000 BCE. Cultivation
in Europe became widespread after 500 ce. The crop was first brought to South
America in 1545, in Chile, and to North America in Port Royal, Acadia in 1606.
The hemp industry flourished in Kentucky, Missouri, and Illinois between 1840
and 1860 because of the strong demand for sailcloth and cordage (Ehrensing 1998).
From the end of the Civil War until 1912, virtually all hemp in the US was produced
in Kentucky. During World War I, some hemp cultivation occurred in several states,
including Kentucky, Wisconsin, California, North Dakota, South Dakota, Minnesota,
Indiana, Illinois, Ohio, Michigan, Kansas, and Iowa (Ehrensing 1998). The second
world war led to a brief revival of hemp cultivation in the Midwest, as well
as in Canada, because the war cut off supplies of fiber (substantial renewed
cultivation also occurred in Germany for the same reason). Until the beginning
of the 19th century, hemp was the leading cordage fiber. Until the middle of
the 19th century, hemp rivaled flax as the chief textile fiber of vegetable
origin, and indeed was described as the king of fiber-bearing plants,the
standard by which all other fibers are measured (Boyce 1900). Nevertheless,
the Marihuana Tax Act applied in 1938 essentially ended hemp production in the
United States, although a small hemp fiber industry continued in Wisconsin until
1958. Similarly in 1938 the cultivation of Cannabis became illegal in
Canada under the Opium and Narcotics Act.

Hemp, grown under license mostly in Canada, is the most publicized new
crop in North America. Until very recently the prohibition against drug forms
of the plant prevented consideration of cultivation of fiber and oilseed cultivars
in Canada. However, in the last 10 years three key developments occurred: (1)
much-publicized recent advances in the legal cultivation of hemp in western
Europe, especially for new value-added products; (2) enterprising farmers and
farm groups became convinced of the agricultural potential of hemp in Canada,
and obtained permits to conduct experimental cultivation; and (3) lobby groups
convinced the government of Canada that narcotic forms of the hemp plant are
distinct and distinguishable from fiber and oilseed forms. In March 1998, new
regulations (under the Controlled Drugs and Substances Act) were provided to
allow the commercial development of a hemp industry in Canada, and since then
more than a thousand licenses have been issued. Hectares licensed for cultivation
for 19982001 were respectively, 2,500, 14,200, 5,487, and 1,355, the decreasing
trend due to a glut of seed produced in 1999 and pessimism over new potential
regulations barring exports to the US. Information on the commercial potential
of hemp in Canada is in Blade (1998), Marcus (1998), and Pinfold Consulting
(1998). In the US, a substantial trade in hemp products has developed, based
on imports of hemp fiber, grain, and oil. The American agricultural community
has observed this, and has had success at the state level in persuading legislators
of the advisability of experimental hemp cultivation as a means of evaluating
the wisdom of re-establishing American hemp production. However, because of
opposition by the federal government, to date there has only been a small experimental
plot in Hawaii. Information on the commercial potential of hemp in the US is
presented in the following.

Cannabis sativa is extremely unusual in the diversity of products for
which it is or can be cultivated. Popular Mechanics magazine (1938) touted hemp
as the new billion dollar crop, stating that it can be used
to produce more than 25,000 products, ranging from dynamite to Cellophane.
Table 1 presents the principal products for which the species is cultivated
in Europe, all of which happen to be based on fiber. This presentation stresses
the products that hold the most promise for North America, which also include
a considerable range of oilseed applications (Table 2; Fig. 1).

BASIC CATEGORIES OF CANNABIS AND THEIR FIELD ARCHITECTURE

Cannabis sativa is an annual wind-pollinated plant, normally dioecious
and dimorphic, although sometimes monoecious (mostly in several modern European
fiber cultivars). Figure 2 presents the basic morphology of the species. Some
special hybrids, obtained by pollinating females of dioecious lines with pollen
from monoecious plants, are predominantly female (so-called all-female,
these generally also produce some hermaphrodites and occasional males). All-female
lines are productive for some purposes (e.g. they are very uniform, and with
very few males to take up space they can produce considerable grain), but the
hybrid seed is expensive to produce. Staminate or male plants tend
to be 10%15% taller and are less robust than the pistillate or female
(note the comparatively frail male in Fig. 3). So prolific is pollen production
that an isolation distance of about 5 km is usually recommended for generating
pure-bred foundation seed. A perigonal bract subtends each female
flower, and grows to envelop the fruit. While small, secretory, resin-producing
glands occur on the epidermis of most of the above-ground parts of the plant,
the glands are very dense and productive on the perigonal bracts, which are
accordingly of central interest in marijuana varieties. The root is a laterally
branched taproot, generally 3060 cm deep, up to 2.5 m in loose soils,
very near the surface and more branched in wet soils. Extensive root systems
are key to the ability of hemp crops to exploit deep supplies of nutrients and
water. The stems are erect, furrowed, and usually branched, with a woody interior,
and may be hollow in the internodes. Although the stem is often woody, the species
is frequently referred to as a herb or forb. Plants vary enormously in height
depending on genetic constitution and environment (Fig. 4), but are typically
15 m (heights of 12 m or more in cultivation have been claimed).

Fig. 4. United States National Institute of Health,
University of Mississippi marijuana plantation site, showing variation in
plant size. A tall fiber-type of hemp plant is shown at left, and a short
narcotic variety (identified as Panama Gold) at right.

There is great variation in Cannabis sativa, because of disruptive domestication
for fiber, oilseed, and narcotic resin, and there are features that tend to
distinguish these three cultigens (cultivated phases) from each other. Moreover,
density of cultivation is used to accentuate certain architectural features.
Figure 5 illustrates the divergent appearances of the basic agronomic categories
of Cannabis in typical field configurations.

Fig. 5. Typical architecture of categories of cultivated Cannabis
sativa. Top left: narcotic plants are generally low, highly branched, and
grown well-spaced. Top right: plants grown for oilseed were traditionally well-spaced,
and the plants developed medium height and strong branching. Bottom left: fiber
cultivars are grown at high density, and are unbranched and very tall. Bottom
center: dual purpose plants are grown at moderate density, tend
to be slightly branched and of medium to tall height. Bottom right: some recent
oilseed cultivars are grown at moderate density and are short and relatively
unbranched. Degree of branching and height are determined both by the density
of the plants and their genetic background.

Highly selected forms of the fiber cultigen possess features maximizing fiber
production. Since the nodes tend to disrupt the length of the fiber bundles,
thereby limiting quality, tall, relatively unbranched plants with long internodes
have been selected. Another strategy has been to select stems that are hollow
at the internodes, with limited wood, since this maximizes production of fiber
in relation to supporting woody tissues. Similarly, limited seed productivity
concentrates the plants energy into production of fiber, and fiber cultivars
often have low genetic propensity for seed output. Selecting monoecious strains
overcomes the problem of differential maturation times and quality of male (staminate)
and female (pistillate) plants (males mature 13 weeks earlier). Male plants
in general are taller, albeit slimmer, less robust, and less productive. Except
for the troublesome characteristic of dying after anthesis, male traits are
favored for fiber production, in contrast to the situation for drug strains
noted below. In former, labor-intensive times, the male plants were harvested
earlier than the females, to produce superior fiber. The limited branching of
fiber cultivars is often compensated for by possession of large leaves with
wide leaflets, which obviously increase the photosynthetic ability of the plants.
Since fiber plants have not generally been selected for narcotic purposes, the
level of intoxicating constituents is usually limited.

An absence of such fiber-strain traits as tallness, limited branching, long
internodes, and very hollow stems, is characteristic of narcotic strains. Drug
forms have historically been grown in areas south of the north-temperate zone,
often close to the equator, and are photoperiodically adapted to a long season.
When grown in north-temperate climates maturation is much-delayed until late
fall, or the plants succumb to cold weather before they are able to produce
seeds. Unlike fiber strains that have been selected to grow well at extremely
high densities, drug strains tend to be less persistent when grown in high concentration
(de Meijer 1994). Drug strains can be very similar in appearance to fiber strains.
However, a characteristic type of narcotic plant was selected in southern Asia,
particularly in India and neighboring countries. This is dioecious, short (about
a meter in height), highly branched, with large leaves (i.e. wide leaflets),
and it is slow to mature. The appearance is rather like a short, conical Christmas
tree.

Until recent times, the cultivation of hemp primarily as an oilseed was largely
unknown, except in Russia. Today, it is difficult to reconstruct the type of
plant that was grown there as an oilseed, because such cultivation has essentially
been abandoned. Oilseed hemp cultivars in the modern sense were not available
until very recently, but some land races certainly were grown specifically for
seeds in Russia. Dewey (1914) gave the following information: The short
oil-seed hemp with slender stems, about 30 inches high, bearing compact clusters
of seeds and maturing in 60 to 90 days, is of little value for fiber production,
but the experimental plants, grown from seed imported from Russia, indicate
that it may be valuable as an oil-seed crop to be harvested and threshed in
the same manner as oil-seed flax. Most hemp oilseed in Europe is currently
obtained from so-called dual usage plants (employed for harvest
of both stem fiber and seeds, from the same plants). Of the European dual-usage
cultivars, Uniko B and Fasamo are particularly suited
to being grown as oilseeds. Very recently, cultivars have been bred specifically
for oilseed production. These include Finola, formerly known as
Fin-314 (Fig. 6) and Anka (Fig. 7), which are relatively
short, little-branched, mature early in north-temperate regions, and are ideal
for high-density planting and harvest with conventional equipment. Dewey (1914)
noted that a Turkish narcotic type of land race called Smyrna was
commonly used in the early 20th century in the US to produce birdseed, because
(like most narcotic types of Cannabis) it is densely branched, producing
many flowers, hence seeds. While oilseed land races in northern Russia would
have been short, early-maturing plants in view of the short growing season,
in more southern areas oilseed landraces likely had moderate height, and were
spaced more widely to allow abundant branching and seed production to develop.
Until Canada replaced China in 1998 as a source of imported seeds for the US,
most seeds used for various purposes in the US were sterilized and imported
from China. Indeed, China remains the largest producer of hempseed. We have
grown Chinese hemp land races, and these were short, branched, adapted to a
very long growing season (i.e. they come into flower very slowly in response
to photoperiodic induction of short days in the fall), and altogether they were
rather reminiscent of Deweys description of Smyrna. Although similar in
appearance to narcotic strains of C. sativa, the Chinese land races we
grew were in fact low in intoxicating constituents, and it may well be that
what Dewey thought was a narcotic strain was not. Although some forms of C.
sativa have quite large seeds, until recently oilseed forms appear to have
been mainly selected for a heavy yield of seeds, usually recognizable by abundant
branching. Such forms are typically grown at lower densities than hemp grown
only for fiber, as this promotes branching, although it should be understood
that the genetic propensity for branching has been selected. Percentage or quality
of oil in the seeds does not appear to have been important in the past, although
selection for these traits is now being conducted. Most significantly, modern
selection is occurring with regard to mechanized harvesting, particularly the
ability to grow in high density as single-headed stalks with very short branches
bearing considerable seed.

Fig. 7. Anka, the first registered North
American bred cultivar of Cannabis sativa. This variety is best suited
for grain production. (Courtesy of the breeder, P. Dragla, and of the Industrial
Hemp Seed Development Company, Chatham, Ontario.)

CONTROLLING THE DRUG ABUSE POTENTIAL OF HEMP

As detailed below, the development of hemp as a new legal crop in North America
must be considered in relation to illicit cultivation, so it is important to
appreciate the scope of the drug situation. Up until the first half of the 20th
century, drug preparations of Cannabis were used predominantly as a recreational
inebriant in poor countries and the lower socio-economic classes of developed
nations. After World War II, marijuana became associated with the rise of a
hedonistic, psychedelic ethos, first in the United States and eventually over
much of the world, with the consequent development of a huge international illicit
market that exceeds the value of the hemp market during its heyday. Table 3
shows the economic significance (dollars generated in the black
market plus dollar cost of control measures) of the illicit drug industry associated
with C. sativa, and contrasts this with the estimated dollar value of
major categories of legitimate uses. In the Netherlands, the annual value of
narcotic hemp cultivation (ca. $10 billion) exceeds the value of tulips (Collins
1999). Marijuana has become the most widely disseminated illicit species in
the world (Schultes and Hofmann 1980). With the exception of alcohol, it is
the most widely used recreational euphoric drug. About 25% of North Americans
are believed to have used Cannabis illegally. According to the US National
Institute on Drug Abuse (www.nida.nih.gov/Infofax/marijuana.html), more than
72 million Americans (33%) 12 years of age and older have tried marijuana. Cultivation,
commerce, and consumption of drug preparations of Cannabis have been
proscribed in most countries during the present century. The cost of enforcing
the laws against Cannabis in North America is in the billions of dollars
annually. In addition, there are substantial social costs, such as adverse effects
on users, particularly those who are convicted. Tragically this includes some
legitimate farmers who, faced with financial ruin because of the unprofitability
of crops being grown, converted to growing marijuana.

zThe global market for hemp-derived products is valued at
between $100 million and $200 million annually (Pinfold Consulting 1998;
De Guzman 2001).

A rather thorough analysis of the scope of the illicit marijuana industry
in Canada for 1998 is reported at www.rcmp-grc.gc.ca/html/drugsituation.htm#Marihuana
and summarized in MacLeod (1999). At least 800 tonnes (t) of marijuana were
grown in Canada in 1998, representing a harvest of 4.7 million flowering plants.
More than 50% of the marijuana available in Canada is grown domestically. An
average mature plant was estimated to produce 170 g of marketable substance.
The value of the Canadian crop is uncertain, but has been estimated to be in
the billions of dollars annually (Heading 1998; MacLeod 1999).

The US Drug Enforcement Administrations online criminal justice statistics
for 2000 (cscmosaic.albany.edu/sourcebook/1995/pdf/t440.pdf) shows the following
seizures and eradication of plants of C. sativa: 40,929 outdoor plots
(2,597,796 plants), 139,580,728 ditchweed (ruderal plants), 2,361 indoor operations
(217,105 plants), for a grand total of 2,814, 903 plants destroyed. Impressively,
the species was grown in all 50 states (including outdoor seizures in every
state except Wyoming)! It is of course impossible to know exactly how much marijuana
is cultivated in the United States, and perhaps only 10% to 20% of the amount
grown is seized. The profitability of the illegal crop is indicated by a comparison
of the cost of a bushel of corn (roughly $2.50) and a bushel of manicured marijuana
(about $70,000; it has been suggested that prices range from $500 a pound, for
low-quality marijuana, to more than $5,000 a pound for boutique
strains like Northern Lights and Afghan Kush). According
to a National Organization for the Reform of Marijuana Laws (NORML) (mir.drugtext.org/marijuananews/marijuana_ranks_fourth_largest_c.htm)
marijuana is at least the fourth most valuable crop in America, outranked only
by corn, soybeans, and hay. It was estimated that 8.7 million marijuana plants
were harvested in 1997, worth $15.1 billion to growers and $25.2 billion on
the retail market (the wholesale value was used to compare marijuana to other
cash crops). Marijuana was judged to be the largest revenue producing crop in
Alabama, California, Colorado, Hawaii, Kentucky, Maine, Rhode Island, Tennessee,
Virginia, and West Virginia, and one of the top five cash crops in 29 other
states.

Cannabis contains a seemingly unique class of chemicals, the cannabinoids,
of which more than 60 have been described, but only a few are psychoactive.
Cannabinoids are produced in specialized epidermal glands, which differ notably
in distribution on different organs of the plant (high concentrations occur
on the upper surface of the young leaves and young twigs, on the tepals, stamens,
and especially on the perigonal bract). Given this distribution, the glands
would seem to be protective of young and reproductive above-ground tissues (the
roots lack glands). Two classes of epidermal glands occurstalked and sessile
(Fig. 8), but in either case the glandular cells are covered by a sheath under
which resin is accumulated, until the sheath ruptures, releasing resin on the
surface. The resin is a sticky mixture of cannabinoids and a variety of terpenes.
The characteristic odor of the plant is due to the abundant terpenes, which
are not psychoactive. The more important cannabinoids are shown in Fig. 9. In
the plant the cannabinoids exist predominantly in the form of carboxylic acids,
which decarboxylate with time or when heated. Delta-9-tetrahydrocannabinol (D9-THC,
or simply THC) is the predominant psychoactive component. Other THC isomers
also occur, particularly D8-THC, which
is also psychoactive. Technically, the euphoric psychological effects of THC
are best described by the word psychotomimetic. Cannabidiol (CBD) is the chief
non-psychotomimetic cannabinoid. A THC concentration in marijuana of approximately
0.9% has been suggested as a practical minimum level to achieve the (illegal)
intoxicant effect, but CBD (the predominant cannabinoid of fiber and oilseed
varieties) antagonizes (i.e. reduces) the effects of THC (Grotenhermen and Karus
1998). Concentrations of 0.3% to 0.9% are considered to have only a small
drug potential (Grotenhermen and Karus 1998). Some cannabinoid races have
been described, notably containing cannabichromene (particularly in high-THC
forms) and cannabigerol monomethyl ether (in some Asian strains). The biosynthetic
pathways of the cannabinoids are not yet satisfactorily elucidated, although
the scheme shown in Fig. 10 is commonly accepted. At least in some strains,
THC is derived from cannabigerol, while in others it may be derived from CBD.
CBN and D8-THC are considered to be degradation
products or analytical artifacts (Pate 1998a).

Fig. 8. Scanning electron micrographs of the abaxial
surface of a perigonal bract (which envelops the fruit). These bracts are
the most intoxicating part of the plant, and may contain 20% THC, dry weight.
The resin is synthesized both in stalked and sessile glands. Multicellular
secretory glands (of phallic appearance), some broken stalks of these (note
cellular appearance), and unicellular cystolith hairs (claw-like structures)
are pictured.

Fig. 9. Some important cannabinoids of cannabis resin.
D9-THC (delta-9 tetrahydrocannabinol)
is the chief intoxicant chemical and predominates in intoxicant strains,
while the isomer D8-THC is usually
present in no more than trace amounts. CBD (cannabidiol) is the chief non-intoxicant
chemical, and predominates in non-intoxicant strains; it has sedative effects.
The non-intoxicant CBN (cannabinol) is a frequent degradation or oxidation
product. The non-intoxicant cannabichromene (CBC) is typically found in
trace amounts in intoxicant strains. The non-intoxicant cannabigerol (CBG)
is considered to be a precursor of the other cannbinoids (see Fig. 10).

Both in Canada and the US, the most critical problem to be addressed for commercial
exploitation of C. sativa is the possible unauthorized drug use of the
plant. Indeed, the reason hemp cultivation was made illegal in North America
was concern that the hemp crop was a drug menace. The drug potential is, for
practical purposes, measured by the presence of THC. THC is the worlds
most popular illicit chemical, and indeed the fourth most popular recreational
drug, after caffeine, alcohol, and nicotine. Industrial hemp is
a phrase that has become common to designate hemp used for commercial non-intoxicant
purposes. Small and Cronquist (1976) split C. sativa into two subspecies:
C. sativa subsp. sativa, with less than 0.3% (dry weight) of THC
in the upper (reproductive) part of the plant, and C. sativa subsp. indica
(Lam.) E. Small & Cronq. with more than 0.3% THC. This classification has
since been adopted in the European Community, Canada, and parts of Australia
as a dividing line between cultivars that can be legally cultivated under license
and forms that are considered to have too high a drug potential. For a period,
0.3% was also the allowable THC content limit for cultivation of hemp in the
Soviet Union. In the US, Drug Enforcement Agency guidelines issued Dec. 7, 1999
expressly allowed products with a THC content of less than 0.3% to enter the
US without a license; but subsequently permissible levels have been a source
of continuing contention. Marijuana in the illicit market typically has a THC
content of 5% to 10% (levels as high as 25% have been reported), and as a point
of interest, a current Canadian government experimental medicinal marijuana
production contract calls for the production of 6% marijuana. As noted above,
a level of about 1% THC is considered the threshold for marijuana to have intoxicating
potential, so the 0.3% level is conservative, and some countries (e.g. parts
of Australia, Switzerland) have permitted the cultivation of cultivars with
higher levels. It should be appreciated that there is considerable variation
in THC content in different parts of the plant. THC content increases in the
following order: achenes (excluding bracts), roots, large stems, smaller stems,
older and larger leaves, younger and smaller leaves, flowers, perigonal bracts
covering both the female flowers and fruits. It is well known in the illicit
trade how to screen off the more potent fractions of the plant in order to increase
THC levels in resultant drug products. Nevertheless, a level of 0.3% THC in
the flowering parts of the plant is reflective of material that is too low in
intoxicant potential to actually be used practically for illicit production
of marijuana or other types of cannabis drugs. Below, the problem of permissible
levels of THC in food products made from hempseed is discussed.

There is a general inverse relationship in the resin of Cannabis between
the amounts of THC present and the amount of the other principal cannabinoid,
CBD. Whereas most drug strains contain primarily THC and little or no CBD, fiber
and oilseed strains primarily contain CBD and very little THC. CBD can be converted
to THC by acid catalyzed cyclization, and so could serve as a starting material
for manufacturing THC. In theory, therefore, low-THC cultivars do not completely
solve the problem of drug abuse potential. In practice, however, the illicit
drug trade has access to easier methods of synthesizing THC or its analogues
than by first extracting CBD from non-drug hemp strains.

Breeding for low THC cultivars in Europe has been reviewed by Bócsa
(1998), Bócsa and Karus (1998), and Virovets (1996). Some researchers
have claimed to have produced essentially THC-free strains, although at present
no commercial cultivar seems to be 100% free of THC. THC content has proven
to be more easily reduced in monoecious than in dioecious varieties. It should
be possible to select THC-free strains, and there has been speculation that
genetic engineering could be helpful in this regard. As a strategic economic
and political tactic, France has been attempting for several years to have the
European Union (EU) adopt legislation forbidding the cultivation of industrial
hemp cultivars with more than 0.1% THC, which would mean that primarily French
varieties would have to be cultivated in Europe. However, the Canadian government
has found that some French material has proven to be excessively high in THC.

There is certainly a need to utilize available germplasm sources in order
to breed suitable cultivars for North America. A list of the 24 approved cultivars
for the 2001 season in Canada is at www.hc-sc.gc.ca/hpb-dgps/therapeut/htmleng/hemp.html.
Most of these are regulated by the European Organization of Economic Cooperation
and Development (OECD). These cultivars are approved for use in
Canada not on agricultural criteria, but merely on the basis that they meet
the THC criterion. Indeed, most of these are unsuitable or only marginally suitable
for Canada (Small and Marcus 2000), and only a very few Canadian cultivars to
date have been created. In Canada, every acquisition of hemp grown at a particular
place and time must be tested for THC content by an independent laboratory and,
under the industrial hemp regulations, fields of hemp with more than 0.3% THC
may require destruction (a slight degree of flexibility is generally exercised).
Importation of experimental hemp lines (i.e. other than the approved cultivars)
requires importation licenses (as well as phytosanitary clearance of the shipment
by the Canadian Food Inspection Agency), and the importation licenses require
an indication that the THC contents are low.

In Canada, the methodology used for analyses and sample collection for THC
analysis of hemp plantings is standardized (at the Health Canada/Therapeutics
Program/Hemp web site at www.hc-sc.gc.ca/hpb-dgps/therapeut/htmleng/hemp.html,
see Industrial Hemp Technical Manual for procedures on sampling
plant materials and chemical procedures for determining THC levels). The regulations
require that one of the dozen independent laboratories licensed for the purpose
conduct the analyses and report the results to Health Canada. Sample collection
is also normally carried out by an independent authorized firm. The Canadian
system of monitoring THC content has rigidly limited hemp cultivation to cultivars
that consistently develop THC levels below 0.3%.

Because C. sativa has been a neglected crop for so long in North America,
there are only negligible genetic resources available on this continent. Most
germplasm stocks of hemp are in Europe, and the largest and most important collection
is the Vavilov Institute gene bank in Leningrad. Figure 11 shows THC concentrations
in the Vavilov collection, as well as in our own collection, largely of European
germplasm. A disturbingly high percentage of the collections have THC levels
higher than 0.3%, making it difficult to incorporate these into breeding programs.

Fig. 11. Frequency histograms of THC concentration in germplasm collections.
Left, collection of E. Small and D. Marcus; of the 167 accessions, 43% had THC
levels >0.3%. Right, the collection of the Vavilov Institute, St. Petersburg;
of the 278 accessions for which chemical analyses were reported in Anonymous
(1975), about 55% had THC levels >0.3%.

Soil characteristics, latitude and climatic stresses have been found to have
significant effects on THC concentrations, and there are seasonal and even diurnal
variations (Small 1979; Pate 1998b). However, the range of THC concentrations
developed by low-THC cultivars (those typically with £0.3% THC) under
different circumstances on the whole is limited, for the most part generally
not varying more than 0.2 percentage points when grown in a range of circumstances,
and usually less (note information in Scheifle et al. 1999; Scheifle 2000, Scheifle
and Dragla 2000). Practically, this has meant in Canadian experience that a
few cultivars have been eliminated from further commercial cultivation because
they sometimes exceed the 0.3% level (Fedora 19 and Futura,
authorized in 2000, have now been removed because some test results in several
years exceeded 0.3%; Finola and Uniko B are under probation
because of elevated levels), but on the whole most of the permitted cultivars
have maintained highly consistent development of quite low levels of THC.

Hemp seeds contain virtually no THC, but THC contamination results from contact
of the seeds with the resin secreted by the epidermal glands on the leaves and
floral parts, and also by the failure to sift away all of the bracts (which
have the highest concentration of THC of any parts of the plant) that cover
the seeds. This results in small levels of THC appearing in hempseed oil and
foods made with the seeds. Although most of the western hemp-growing world uses
0.3% THC as a maximum concentration for authorized cultivation of hemp plants,
regulations in various countries allow only a much lower level of THC in human
food products manufactured from the seeds. Currently, up to 10 ppm THC is permitted
in seeds and oil products used for food purposes in Canada. In Germany, more
stringent limits were set for food in 2000: 5 ppm in food oil, 0.005 ppm in
beverages, and 0.15 ppm in all other foods. The US Drug Enforcement Administration
published new regulations on hemp in the Federal Register on October 9th 2001
that in effect 4 months later would ban the food use of hemp in the US because
any amount of THC would be unacceptable in foods (follow links at www.hempreport.com/).
These proposals are currently being challenged by the hemp industry. Limits
have been set because of concerns about possible toxicity and interference with
drug tests (Grotenhermen et al. 1998). An extensive analysis of literature dealing
with the toxicity of hemp is in Orr and Starodub (1999; see Geiwitz 2001 for
an analysis). Because hemp food products are considered to have great economic
potential, there is considerable pressure on the hemp industry in North America
to reduce THC levels.

The Drug Enforcement Agency and the Office of National Drug Control Policy
of the US raised concerns over tests conducted from 1995 to 1997 that showed
that consumption of hempseed products available during that period led to interference
with drug-testing programs for marijuana use. Federal US programs utilize a
THC metabolite level of 50 parts per billion in urine. Leson (2000) found that
this level was not exceeded by consuming hemp products, provided that THC levels
are maintained below 5 ppm in hemp oil, and below 2 ppm in hulled seeds. Nevertheless
the presence of even minute trace amounts of THC in foods remains a tool that
can be used by those wishing to prevent the hemp oilseed industry from developing.

FIBER USES

Based on world production of fibers in 1999, about 54.5% was synthetic (of
which 60.3% was polyester), 42.9% was plant fiber (of which 78.5% was cotton),
and 2.6% was wool (Karus 2000). In addition to cotton, flax is the only other
significant plant fiber crop grown in temperate regions of the world (kenaf
has received some enthusiastic backing in the southern US in recent years, but
is most cheaply produced in India, Bangladesh, and China). Flax held 2.7% of
the world plant fiber market in 1999, while hemp had only 0.3% (Karus 2000).
Hemp fiber can potentially replace other biological fibers in many applications,
but also, as noted below, can sometimes compete with minerals such as glass
fiber and steel. As forests diminish, cultivation of annual plants as fiber
sources is likely to increase. While crop residues like cereal straw will probably
supply much of the need, specialty fiber plants such as hemp also have potential.
The four conditions that will need to be met are (after Bolton 1995): (1) the
material should be produced at a large enough scale; (2) the price should be
low enough; (3) the fiber characteristics should be adequate for the end use;
and (4) proven technology should be available for the processing of the new
raw material. Of these criteria only point 3 is adequately met at this time
for hemp in North America, but this is to be expected in a crop that has only
begun to be cultivated after an absence of many years.

One of the reasons hemp fiber has been valued is because of its length. The
primary bast fibers in the bark are 540 mm long, and are amalgamated in
fiber bundles which can be 15 m long (secondary bast fibers are about
2 mm long). The woody core fibers are shortabout 0.55 mmand like
hardwood fibers are cemented together with considerable lignin. The core fibers
are generally considered too short for high grade paper applications (a length
of 3 mm is considered ideal), and too much lignin is present. While the long
bast fibers have been used to make paper almost for 2 millennia, the woody core
fibers have rarely been so used. Nevertheless it has been suggested that the
core fibers could be used for paper making, providing appropriate technology
was developed (de Groot et al. 1998). In any event, the core fibers, have found
a variety of uses, as detailed below. The long, lignin-poor bast fibers also
have considerable potential to be used in many non-paper, non-textile applications,
as noted below.

Selection for fiber has resulted in strains that have much more bark fiber
tissues and much less woody core than encountered in narcotic strains, oilseed
strains, and wild plants (Fig. 12). In non-fiber strains of Cannabis,
bark can be less than one quarter of the stem tissues (i.e. more than three
quarters can be woody core). By contrast, in fiber strains half of the stem
tissues can be bark, and more than half of this can be the desirable long primary
fibers (de Meijer 1995). Non-fiber strains rarely have as much as 15% fiber
in the bark.

Fig. 12. Cross sections of stems at internodes of a fiber plant (left)
and of a narcotic plant (right). Fiber cultivars have stems that are more hollow
at the internodes, i.e. less wood, since this allows more energy to be directed
into the production of bark fiber.

Other desirable features of hemp fibers are strength and durability (particularly
resistance to decay), which made hemp useful in the past for rope, nets, sail-cloth,
and oakum for caulking. During the age of sailing ships, Cannabis was
considered to provide the very best of canvas, and indeed this word is derived
from Cannabis. Several factors combined to decrease the popularity of
hemp in the late 19th and early 20th centuries. Increasing limitation of cheap
labor for traditional production in Europe and the New World led to the creation
of some mechanical inventions, but too late to counter growing interest in competitive
crops. Development of other natural fibers as well as synthetic fibers increased
competition for hemps uses as a textile fiber and for cordage. Hemp rag
had been much used for paper, but the 19th century introduction of the chemical
woodpulping process considerably lowered demand for hemp. The demise of the
sail diminished the market for canvas. Increasing use of the plant for drugs
gave hemp a bad image. All this led to the discontinuation of hemp cultivation
in the early and middle parts of the 20th century in much of the world where
cheap labor was limited. In the 19th century softer fabrics took over the clothing
market, and today, hemp constitutes only about 1% of the natural fiber market.
At least some production of hemp for fiber still occurs in Russia, China, the
Ukraine, Poland, Hungary, the countries of the former Yugoslavia, Romania, Korea,
Chile, and Peru. There has been renewed interest in England, Australia, and
South Africa in cultivating fiber hemp. Italy has an outstanding reputation
for high-quality hemp, but productivity has waned for the last several decades.
In France, a market for high-quality paper, ironically largely cigarette paper,
has developed (such paper is completely free of the intoxicating resin). Modern
plant breeding in Europe has produced several dozen hemp strains, although by
comparison with other fiber crops there are relatively few described varieties
of hemp. Since World War II, breeding has been concerned most particularly with
the development of monoecious varieties. Gehl (1995) reviewed fiber hemp development
in Canada in the early 20th century, and concluded that the prospects for a
traditional fiber industry were poor. However, as outlined below, there are
now many non-traditional usages for hemp fiber which require consideration.
Hemp long fiber is one of the strongest and most durable of natural fibers,
with high tensile strength, wet strength, and other characteristics that make
it technically suited for various industrial products (Karus and Leson 1996).

From 1982 to 2002 the EU provided the equivalent of about 50 million dollars
to develop new flax and hemp harvesting and fiber processing technologies (Karus
et al. 2000). Because of the similarities of flax and hemp, the technologies
developed for one usually are adaptable to the other. In addition, various European
nations and private firms contributed to the development of hemp technologies.
Accordingly, Europe is far more advanced in hemp development with respect to
all fiber-based applications than other parts of the world. The EU currently
dedicates about 30,000 ha to hemp production. France is the leading country
in hemp cultivation in the EU, and 95% of the non-seed production is used for
specialty pulp as described below. Harvesting and processing machinery
for fiber hemp is highly advanced in Europe, and some has been imported into
Canada. However, there is insufficient fiber processing capacity to handle hemp
produced in Canada.

Textiles

Hemp is a bast fiber crop, i.e. the most desirable (long) fibers
are found in the phloem-associated tissues external to the phloem, just under
the bark. The traditional and still major first step in fiber extraction
is to ret (rot) away the softer parts of the plant, by exposing
the cut stems to microbial decay in the field (dew retting, shown
in Figs. 46 and 47) or submerged in water (water retting,  shown
in Fig. 13). The result is to slough off the outer parts of the stem and to
loosen the inner woody core (the hurds) from the phloem fibers (Fig.
14). Water retting has been largely abandoned in countries where labor is expensive
or environmental regulations exist. Water retting, typically by soaking the
stalks in ditches, can lead to a high level of pollution. Most hemp fiber used
in textiles today is water retted in China and Hungary. Retting in tanks rather
than in open bodies of water is a way of controlling the effluents while taking
advantage of the high-quality fiber that is produced. Unlike flax, hemp long
fiber requires water retting for preparation of high-quality spinnable fibers
for production of fine textiles. Improved microorganisms or enzymes could augment
or replace traditional water retting. Steam explosion is another potential technology
that has been experimentally applied to hemp (Garcia-Jaldon et al. 1998). Decorticated
material (i.e. separated at least into crude fiber) is the raw material, and
this is subjected to steam under pressure and increased temperature which explodes
(separates) the fibers so that one has a more refined (thinner) hemp fiber that
currently is only available from water retting. Even when one has suitably separated
long fiber, specialized harvesting, processing, spinning and weaving equipment
are required for preparing fine hemp textiles. The refinement of equipment and
new technologies are viewed as offering the possibility of making fine textile
production practical in western Europe and North America, but at present China
controls this market, and probably will remain dominant for the foreseeable
future.

Fig. 13. Water retting of hemp in Yugoslavia. (Courtesy of Dr.
J. Berenji, Institute of Field and Vegetable Crops, Novi Sad.)

Fig. 14. Fiber in retted hemp stem. This stem was bent sharply
after retting, breaking the woody central portion (hurds), leaving the bark
fibers unbroken. The two portions of stem are separated in this photograph,
and are joined by the tough bark fibers.

There are practical, if cruder alternatives to separate the long fiber for
high-quality textile production, but in fact such techniques are used mostly
for non-textile applications. This involves production of whole fibers
(i.e. harvesting both the long fibers from the cortex and the shorter fibers
from throughout the stem), and technologies that utilize shortened hemp fibers.
This approach is currently dominant in western Europe and Canada, and commences
with field dew retting (typically 23 weeks). A principal limitation is
climaticthe local environment should be suitably but not excessively moist
at the close of the harvest season. Once stalks are retted, dried, and baled,
they are processed to extract the fiber. In traditional hemp processing, the
long fiber was separated from the internal woody hurds in two steps, breaking
(stalks were crushed under rollers that broke the woody core into short pieces,
some of which were separated) and scutching (the remaining hurds, short fibers
(tow) and long fibers (line fiber,  long-line
fiber) were separated). A single, relatively expensive machine called
a decorticator can do these two steps as one. In general in the EU and Canada,
fibers are not separated into tow and line fibers, but are left as whole
fiber. In western Europe, the fiber is often cottonized, i.e.
chopped into short segments the size of cotton and flax fiber, so that the fibers
can be processed on flax processing machinery, which is very much better developed
than such machinery is for hemp. In North America the use of hemp for production
of even crude textiles is marginal. Accordingly, the chief current fiber usages
of North American, indeed of European hemp, are non-textile.

Although always sold at a premium price, hemp clothing has a natural appeal
to a sector of the population. Hemp clothes are resistant to abrasion, but are
typically abrasive. However, appropriate processing and blending with other
natural fibers has significantly improved the feel of the product,
and in China hemp textiles indistinguishable from fine linens in texture are
available. Weaving of hemp fibers into textiles and apparel is primarily done
in China, Hungary, Romania, Russia, and the Ukraine. Processing costs are higher
for industrial hemp because the fibers vary from the standard specifications
for fiber length and diameter established for the equipment used in most textile
and apparel factories, necessitating the use of specialty machines. The North
American hemp apparel industry today is based on fiber, yarn, and fabrics imported
from Eastern Europe and China. The extraction technology and spinning facilities,
to say nothing of much lower labor costs, make it very difficult for the potential
development of a hemp textile industry in North America. The fact that spinning
facilities for natural fibers are so concentrated in China is making it increasingly
difficult to competitively produce hemp fabrics elsewhere. This of course lessens
the value-added future of growing hemp for a potential textile industry in North
America. It is possible, however, that new technologies could change this situation,
and especially in the EU development is underway to establish a fledgling domestic
hemp textile industry. In addition to textiles used in clothing, coarser woven
cloth (canvas) is used for upholstery, bags, sacks, and tarpaulins. There is
very little effort in North America to produce such woven products, and non-woven
material (Fig. 15) can be more easily produced. Hempline in Ontario, the first
firm to grow hemp for commercial purposes in North America since the second
word war (starting with experimental cultivation in 1994), is the exception,
and is concerned with production of fiber for upholstery and carpeting.

Pulp and Paper

Van Roekel (1994) has pointed out that Egyptian papyrus sheets are not paper,
because the fiber strands are woven, not wet-laid; the oldest surviving
paper is over 2,000 years of age, from China, and was made from hemp fiber (Fleming
and Clarke 1998). Until the early 19th century, hemp, and flax were the chief
paper-making materials. In historical times, hemp rag was processed into paper.
Using hemp directly for paper was considered too expensive, and in any event
the demand for paper was far more limited than today. Wood-based paper came
into use when mechanical and chemical pulping was developed in the mid 1800s
in Germany and England. Today, at least 95% of paper is made from wood pulp.

The pulp and paper industry based on wood has considered the use of hemp for
pulp, but only on an experimental basis. Hemps long fibers could make
paper more recyclable. Since virgin pulp is required for added strength in the
recycling of paper, hemp pulp would allow for at least twice as many cycles
as wood pulp. However, various analyses have concluded that the use of hemp
for conventional paper pulp is not profitable (Fertig 1996).

Specialty pulp is the most important component of the hemp industry
of the EU, and is expected to remain its core market for the foreseeable future.
The most important specialty pulp products made from hemp are cigarette paper
(Fig. 16), bank notes, technical filters, and hygiene products. Other uses include
art papers and tea bags. Several of these applications take advantage of hemps
high tear and wet strength. This is considered to be a highly stable, high-priced
niche market in Europe, where hemp has an 87% market share of the specialty
pulp sector (Karus et al. 2000). In Europe, decortication/refining machines
are available that can produce 10 t/hour of hemp fiber suitable for such pulp
use. North American capacity for hemp pulp production and value-added processing
is much more limited than that of Europe, and this industry is negligible in
North America.

Hemp paper is useful for specialty applications such as currency and cigarette
papers where strength is needed. The bast fiber is of greatest interest to the
pulp and paper industry because of its superior strength properties compared
to wood. However, the short, bulky fibers found in the inner part of the plant
(hurds) can also be used to make cheaper grades of paper, apparently without
greatly affecting quality of the printing surface. Hemp is not competitive for
newsprint, books, writing papers, and general paper (grocery bags, coffee cups,
napkins), although there is a specialty or novelty market for those specifically
wishing to support the hemp industry by purchasing hemp writing or printing
paper despite the premium price (Fig. 17).

Fig. 17. Hemp paper products (writing paper, notebook, envelopes).

A chief argument that has been advanced in favor of developing hemp as a paper
and pulp source has been that as a non-wood or tree-free fiber source, it can
reduce harvesting of primary forests and the threat to associated biodiversity.
It has been claimed that hemp produces three to four times as much useable fiber
per hectare per annum as forests. However, Wong (1998) notes evidence that in
the southern US hemp would produce only twice as much pulp as does a pine plantation
(but see discussion below on suitability of hemp as a potential lumber substitute
in areas lacking trees).

Hemp paper is high-priced for several reasons. Economies of scale are such
that the supply of hemp is minute compared to the supply of wood fiber. Hemp
processing requires non-wood-based processing facilities. Hemp paper is typically
made only from bast fibers, which require separation from the hurds, thereby
increasing costs. This represents less than 50% of the possible fiber yield
of the plant, and future technologies that pulp the whole stalks could decrease
costs substantially. Hemp is harvested once a year, so that it needs to be stored
to feed mills throughout the year. Hemp stalks are very bulky, requiring much
handling and storage. Transportation costs are also very much higher for hemp
stalks than for wood chips. Waste straw is widely available from cereals and
other crops, and although generally not nearly as desirable as hemp, can produce
bulk pulp far more cheaply than can be made from hemp. In addition to agricultural
wastes, there are vast quantities of scrub trees, especially poplar, in northern
areas, that can supply large amounts of low-quality wood fiber extremely cheaply.
Moreover, in northern areas fast-growing poplars and willows can be grown, and
such agro-forestry can be very productive and environmentally benign. And, directly
or indirectly, the lumber/paper industry receives subsidies and/or supports,
which is most unlikely for hemp.

Plastic Composites for the Automobile and Other Manufacturing Sectors

With respect to fiber, a composite is often defined as a material
consisting of 30%70% fiber and 70%30% matrix (Bolton 1995). However,
in North America particleboards and fiberboards, which generally contain less
than 10% adhesive or matrix, are sometimes referred to as composites. This section
addresses plastic-type composites. In plastics, fibers are introduced to improve
physical properties such as stiffness, impact resistance, bending and tensile
strength. Man-made fibers of glass, kevlar and carbon are most commonly used
today, but plant fibers offer considerable cost savings along with comparable
strength properties.

Plastic composites for automobiles are the second most important component
of the hemp industry of the EU. Natural fibers in automobile composites are
used primarily in press-molded parts (Fig. 18). There are two widespread technologies.
In thermoplastic production, natural fibers are blended with polypropylene fibers
and formed into a mat, which is pressed under heat into the desired form. In
thermoset production the natural fibers are soaked with binders such as epoxy
resin or polyurethane, placed in the desired form, and allowed to harden through
polymerization. Hemp has also been used in other types of thermoplastic applications,
including injection molding. The characteristics of hemp fibers have proven
to be superior for production of molded composites. In European manufacturing
of cars, natural fibers are used to reinforce door panels, passenger rear decks,
trunk linings, and pillars. In 1999 over 20,000 t of natural fiber were used
for these purposes in Europe, including about, 2,000 t of hemp. It has been
estimated that 510 kg of natural fibers can be used in the molded portions
of an average automobile (excluding upholstery). The demand for automobile applications
of hemp is expected to increase considerably, depending on the development of
new technologies (Karus et al. 2000).

Fig. 18. C-class Mercedes-Benz automobiles have more than 30 parts made
of natural fibers, including hemp. (Courtesy of T. Schloesser, Daimler-Chrysler.)

Henry Ford recognized the utility of hemp in early times. In advance of todays
automobile manufacturers, he constructed a car with certain components made
of resin stiffened with hemp fiber (Fig. 19). Rather ironically in view of todays
parallel situation, Henry Fords hemp innovations in the 1920s occurred
at a time of crisis for American farms, later to intensify with the depression.
The need to produce new industrial markets for farm products led to a broad
movement for scientific research in agriculture that came to be labeled Farm
Chemurgy, that today is embodied in chemical applications of crop constituents.

Fig. 19. Henry Ford swinging an axe at his 1941 car to demonstrate the
toughness of the plastic trunk door made of soybean and hemp. (From the collections
of Henry Ford Museum & Greenfield Village.)

There is also considerable potential for other industries using hemp in the
manner that the automobile industry has demonstrated is feasible. Of course,
all other types of transportation vehicles from bicycles to airplanes might
make use of such technology. Natural fibers have considerable advantages for
use in conveyance (Karus et al. 2000): low density and weight reduction, favorable
mechanical, acoustical, and processing properties (including low wear on tools),
no splintering in accidents, occupational health benefits (compared to glass
fibers), no off-gassing of toxic compounds, and price advantages. Additional
types of composite using hemp in combination with other natural fibers, post-industrial
plastics or other types of resins, are being used to produce non-woven matting
for padding, sound insulation, and other applications.

Building Construction Products

Thermal Insulation. Thermal insulation products (Fig. 20, 21) are the
third most important sector of the hemp industry of the EU. These are in very
high demand because of the alarmingly high costs of heating fuels, ecological
concerns about conservation of non-renewable resources, and political-strategic
concerns about dependence on current sources of oil. This is a market that is
growing very fast, and hemp insulation products are increasing in popularity.
In Europe, it has been predicted that tens of thousands of tonnes will be sold
by 2005, shared between hemp and flax (Karus et al. 2000).

Fiberboard. In North America the use of nonwood fibers in sheet fiberboard
(pressboard or composite board) products is relatively
undeveloped. Flax, jute, kenaf, hemp, and wheat straw can be used to make composite
board. Wheat straw is the dominant nonwood fiber in such applications. Although
it might seem that hemp bast fibers are desirable in composite wood products
because of their length and strength, in fact the short fibers of the hurds
have been found to produce a superior product (K. Domier, pers. commun.). Experimental
production of hemp fiberboard has produced extremely strong material (Fig. 22).
The economic viability of such remains to be tested. Molded fiberboard products
are commercially viable in Europe (Fig. 23), but their potential in North America
remains to be determined.

Cement (Concrete) and Plaster. Utilizing the ancient technique of reinforcing
clay with straw to produce reinforced bricks for constructing domiciles, plant
fibers have found a number of comparable uses in modern times. Hemp fibers added
to concrete increase tensile strength while reducing shrinkage and cracking.
Whole houses have been made based on hemp fiber (Fig. 24, 25). In North America,
such usage has only reached the level of a cottage industry. Fiber-reinforced
cement boards and fiber-reinforced plaster are other occasionally produced experimental
products. Hemp fibers are produced at much more cost than wood chips and straw
from many other crops, so high-end applications requiring high strength seem
most appropriate.

Fig. 24. New building in France being constructed entirely
of hemp. Wall castings are a conglomerate of Isochanvre® lime-hemp,
for production of a 200 mm thick monolithic wall without an interior wall
lining. (Courtesy of M. Périer, Chènovotte Habitat, France.)

Fig. 25. The hemp house under construction
on the Oglala Lakota Nation (Pine Ridge Reservation), South Dakota. Foundation
blocks for the house are made with hemp fiber as a binder in cement. Stucco
is also of hemp. Shingles are 60% hemp in a synthetic polymer. Hemp insulation
is used throughout. (Courtesy of Oglala Sioux Tribe, Slim Butte Land Use
Association, and S. Sauser.)

The above uses are based on hemp as a mechanical strengthener of materials.
Hemp can also be chemically combined with materials. For example, hemp with
gypsum and binding agents may produce light panels that might compete with drywall.
Hemp and lime mixtures make a high quality plaster. Hemp hurds are rich in silica
(which occurs naturally in sand and flint), and the hurds mixed with lime undergo
mineralization, to produce a stone-like material. The technology is most advanced
in France (Fig. 26). The mineralized material can be blown or poured into the
cavities of walls and in attics as insulation. The foundations, walls, floors,
and ceilings of houses have been made using hemp hurds mixed with natural lime
and water. Sometimes plaster of Paris (pure gypsum), cement, or sand is added.
The resulting material can be poured like concrete, but has a texture vaguely
reminiscent of corkmuch lighter than cement, and with better heat and
sound-insulating properties. An experimental ceramic tile made of
hemp has recently been produced (Fig. 27).

Animal Bedding

The woody core (hurds, sometimes called shives) of hemp makes remarkably good
animal bedding (Fig. 28, 29). The hurds are sometimes molded into small pellets
for bedding applications (Fig. 30). Such appears to be unsurpassed for horse
bedding, and also make an excellent litter for cats and other pets (Fig. 31).
The hurds can absorb up to five times their weight in moisture (typically 50%
higher than wood shavings), do not produce dust (following initial dust removal),
and are easily composted. Hemp bedding is especially suited to horses allergic
to straw. In Europe, the animal bedding market is not considered important (Karus
et al. 2000), but in North America there are insufficient hemp hurds available
to meet market demand.

The high absorbency of hemp hurds has led to their occasional use as an absorbent
for oil and waste spill cleanup. Hemp as an industrial absorbent has generated
some interest in Alberta, for use in land reclamation in the oil and gas industry.
Because hemp hurds are a costly product, it is likely that animal bedding will
remain the most important application.

Geotextiles

Geotextiles or agricultural textiles include (1) ground-retaining,
biodegradable matting designed to prevent soil erosion, especially to stabilize
new plantings while they develop root systems along steep highway banks to prevent
soil slippage (Fig. 32); and (2) ground-covers designed to reduce weeds in planting
beds (in the manner of plastic mulch). At present the main materials used are
polymeric (polythene, spun-blown polypropylene) and some glass fiber and natural
fibers. Both woven and non-woven fibers can be applied to geotextiles; woven
and knitted materials are stronger and the open structure may be advantageous
(e.g. in allowing plants to grow through), but non-wovens are cheaper and better
at suppressing weeds. Flax and hemp fibers exposed to water and soil have been
claimed to disintegrate rapidly over the course of a few months, which would
make them unacceptable for products that need to have long-term stability when
exposed to water and oil. Coco (coir) fiber has been said to be much more suitable,
due to higher lignin content (40%50%, compared to 2%5% in bast fibers);
these are much cheaper than flax and hemp fibers (Karus et al. 2000). However,
this analysis does not do justice to the developing hemp geotextile market.
Production of hemp erosion control mats is continuing in both Europe and Canada.
Given the reputation for rot resistance of hemp canvas and rope, it seems probable
that ground matting is a legitimate use. Moreover, the ability to last outdoors
for many years is frequently undesirable in geotextiles. For example, the widespread
current use of plastic netting to reinforce grass sod is quite objectionable,
the plastic persisting for many years and interfering with lawn care. Related
to geotextile applications is the possibility of using hemp fiber as a planting
substrate (biodegradable pots and blocks for plants), and as biodegradable twine
to replace plastic ties used to attach plants to supporting poles. Still another
consideration is the green ideal of producing locally for local
needs; by this credo, hemp is preferable in temperate regions to the use of
tropical fibers, which need to be imported.

OILSEED USES

The cultivation of hemp in the EU is heavily weighted toward fiber production
over oilseed production. In 1999, the EU produced about 27,000 t of hemp fiber,
but only about 6,200 t of hemp seeds, mostly in France, and 90% of this was
used as animal feed (Karus et al. 2000). The seeds (Fig. 33) have traditionally
been employed as bird and poultry feed, but feeding the entire seeds to livestock
has been considered to be a poor investment because of the high cost involved
(although subsidization in Europe allows such usage, especially in France where
hemp seeds are not legally permitted in human food). As pointed out later, higher
yield and better harvesting practices may make whole hempseed an economical
livestock feed. Moreover, seed cake left after expressing the oil is an excellent
feed. Efforts are underway in Europe to add value in the form of processed products
for hemp, especially cosmetics and food but, as noted below, the North American
market is already quite advanced in oilseed applications.

Fig. 33. Seeds (achenes) of hemp, with a match for scale.

In the EU and Canada, hemp has often been grown as a dual-purpose crop, i.e.
for both fiber and oilseed. In France, dual purpose hemp is typically harvested
twiceinitially the upper seed-bearing part of the stems is cut and threshed
with a combine, and subsequently the remaining stems are harvested. Growing
hemp to the stage that mature seeds are present compromises the quality of the
fiber, because of lignification. As well, the hurds become more difficult to
separate. The lower quality fiber, however, is quite utilizable for pulp and
non-woven usages.

In North America, oilseed hemp has several advantages over fiber hemp. Hemp
seed and oil can fetch higher prices than hemp fiber. Hemp seed can be processed
using existing equipment, while processing of hemp fiber usually requires new
facilities and equipment.

Canada is specialized on oilseed production and processing, so that hemp oil
and grain are much more suitable than fiber. Because of the extensive development
of oilseeds in Canada, there is extensive capacity to produce high-quality cold-pressed
hemp oil. Canada in the last 5 years has made great advances in the growing,
harvesting, and processing of hempseed, and indeed has moved ahead of the EU
in the development of raw materials and products for the natural foods, nutraceuticals,
and cosmetics industries. In the EU, a yield of 1 t/ha is considered good. In
Canada, extraordinary yields of 1.5 t/ha have been realized, at least locally,
although in the initial years of hempseed development in Canada yields were
often less than 500 kg/ha. In 1999, the year of largest Canadian hemp acreage,
yields averaged 900 kg/ha. (Ideally, hemp seed yield should be based on air
dry weightwith about 12% moisture. Hemp yields are sometime uncertain,
and could be exaggerated by as much as 50% when moist weights are reported.)

Canadian experience with growing hemp commercially for the last 4 years has
convinced many growers that it is better to use a single-purpose cultivar, seed
or fiber, than a dual-purpose cultivar. The recent focus of Canadian hemp breeders
has been to develop cultivars with high seed yields, low stature (to avoid channeling
the plants energy into stalk, as is the case in fiber cultivars), early
maturation (for the short growing seasons of Canada), and desirable fatty acid
spectrum (especially gamma-linolenic acid).

Food

Dehulled (i.e. hulled) hemp seed is a very recent phenomenon, first produced
in quantity in Europe. Hemp seeds have been used as food since ancient times,
but generally the whole seed, including the hull, was eaten. Hemp seed was a
grain used in ancient China, although there has been only minor direct use of
hemp seed as food by humans. In the past, hemp seed has generally been a food
of the lower classes, or a famine food. Peanut-butter type preparations have
been produced from hemp seed in Europe for centuries, but were rather gritty
since technology for removing the hulls was rudimentary. Modern seed dehulling
using mechanical separation produces a smooth, white, gritless hemp seed meal
that needs no additional treatment before it is consumed. It is important to
understand, therefore, that the quality of modern hemp seed for human consumption
far exceeds anything produced historically. This seed meal should be distinguished
from the protein-rich, oil-poor seed cake remaining after oil has been expressed,
that is used for livestock feed. The seed cake is also referred to as seed
meal, and has proven to be excellent for animals (Mustafa et al. 1999).

Hemp seeds have an attractive nutty taste, and are now incorporated into many
food preparations (Fig. 34), often mimicking familiar foods. Those sold in North
America include nutritional (granola-type) or snack bars, nut butters
and other spreads, bread, pretzels, cookies, yogurts, pancakes, porridge, fruit
crumble, frozen dessert (ice cream), pasta, burgers, pizza, salt
substitute, salad dressings, mayonnaise, cheese, and beverages (milk,
lemonade, beer, wine, coffee nog).
Hemp seed is often found canned or vacuum-packed (Fig. 35). Alcoholic beverages
made with hemp utilize hempseed as a flavorant. Hemp food products currently
have a niche market, based particularly on natural food and specialty food outlets.

Fig. 34. Some North American food products made with
hemp seed and/or hemp seed oil.

Edible Oil

The use of Cannabis for seed oil (Fig. 36) began at least 3 millennia
ago. Hempseed oil is a drying oil, formerly used in paints and varnishes and
in the manufacture of soap. Present cultivation of oilseed hemp is not competitive
with linseed for production of oil for manufacturing, or to sunflower and canola
for edible vegetable oil. However, as noted below, there are remarkable dietary
advantages to hempseed oil, which accordingly has good potential for penetrating
the salad oil market, and for use in a very wide variety of food products. There
is also good potential for hemp oil in cosmetics and skin-care products.

Foreign sources, China in particular, can produce hemp seed cheaply, but imported
seed must be sterilized, and the delays this usually requires are detrimental.
Seed that has been sterilized tends to go rancid quickly, and so it is imperative
that fresh seed be available, a great advantage for domestic production. An
additional extremely significant advantage that domestic producers have over
foreign sources is organic production, which is important for the image desired
by the hemp food market. Organic certification is much more reliable in North
America than in the foreign countries that offer cheap seeds. Whereas China
used to supply most of the hempseed used for food in North America, Canadian-grown
seeds have taken over this market.

About half of the world market for hemp oil is currently used for food and
food supplements (de Guzman 2001). For edible purposes, hempseed oil is extracted
by cold pressing. Quality is improved by using only the first pressing, and
minimizing the number of green seeds present. The oil varies in color from off-yellow
to dark green. The taste is pleasantly nutty, sometimes with a touch of bitterness.
Hemp oil is high in unsaturated fatty acids (of the order of 75%), which can
easily oxidize, so it is unsuitable for frying or baking. The high degree of
unsaturation is responsible for the extreme sensitivity to oxidative rancidity.
The oil has a relatively short shelf life. It should be extracted under nitrogen
(to prevent oxidation), protected from light by being kept in dark bottles,
and from heat by refrigeration. Addition of anti-oxidants prolongs the longevity
of the oil. Steam sterilization of the seeds, often required by law, allows
air to penetrate and so stimulates rancidity. Accordingly, sterilized or roasted
hemp seeds, and products made from hemp seed that have been subjected to cooking,
should be fresh. The value of hemp oil from the point of view of the primary
components is discussed below. In addition, it has been suggested that other
components, including trace amounts of terpenes and cannabinoids, could have
health benefits (Leizer et al. 2000). According to an ancient legend (Abel 1980),
Buddha, the founder of Buddhism, survived a 6-year interval of asceticism by
eating nothing but one hemp seed daily. This apocryphal story holds a germ of
truthhemp seed is astonishingly nutritional.

Fatty Acids. The quality of an oil or fat is most importantly determined
by its fatty acid composition. Hemp is of high nutritional quality because it
contains high amounts of unsaturated fatty acids, mostly oleic acid (C18:1,
10%16%), linoleic acid (C18:2, 50%60%), alpha-linolenic acid (C18:3,
20%25%), and gamma-linolenic acid (C18:3, 2%5%) (Fig. 37). Linoleic
acid and alpha-linolenic acid are the only two fatty acids that must be ingested
and are considered essential to human health (Callaway 1998). In contrast to
shorter-chain and more saturated fatty acids, these essential fatty acids do
not serve as energy sources, but as raw materials for cell structure and as
precursors for biosynthesis for many of the bodys regulatory biochemicals.
The essential fatty acids are available in other oils, particularly fish and
flaxseed, but these tend to have unpleasant flavors compared to the mellow,
slightly nutty flavor of hempseed oil. While the value of unsaturated fats is
generally appreciated, it is much less well known that the North American diet
is serious nutritionally unbalanced by an excess of linoleic over alpha-linonenic
acid. In hempseed, linoleic and alpha-linolenic occur in a ratio of about 3:1,
considered optimal in healthy human adipose tissue, and apparently unique among
common plant oils (Deferne and Pate 1996). Gamma-linolenic acid or GLA is another
significant component of hemp oil (1%6%, depending on cultivar). GLA is
a widely consumed supplement known to affect vital metabolic roles in humans,
ranging from control of inflammation and vascular tone to initiation of contractions
during childbirth. GLA has been found to alleviate psoriasis, atopic eczema,
and mastalgia, and may also benefit cardiovascular, psychiatric, and immunological
disorders. Ageing and pathology (diabetes, hypertension, etc.) may impair GLA
metabolism, making supplementation desirable. As much as 15% of the human population
may benefit from addition of GLA to their diet. At present, GLA is available
in health food shops and pharmacies primarily as soft gelatin capsules of borage
or evening primrose oil, but hemp is almost certainly a much more economic source.
Although the content of GLA in the seeds is lower, hemp is far easier to cultivate
and higher-yielding. It is important to note that hemp is the only current natural
food source of GLA, i.e. not requiring the consumption of extracted dietary
supplements. There are other fatty acids in small concentrations in hemp seed
that have some dietary significance, including stearidonic acid (Callaway et
al. 1996) and eicosenoic acid (Mölleken and Theimer 1997). Because of the
extremely desirable fatty acid constitution of hemp oil, it is now being marketed
as a dietary supplement in capsule form (Fig. 38).

Fig. 37. Content of principal fatty acids in hempseed
oil, based on means of 62 accessions grown in southern Ontario (reported
in Small and Marcus 2000).

Fig. 38. Hemp oil in capsule form sold as a dietary
supplement.

Tocopherols. Tocopherols are major antioxidants in human serum. Alpha-
beta-, gamma- and delta-tocopherol represent the vitamin E group. These fat-soluble
vitamins are essential for human nutrition, especially the alpha-form, which
is commonly called vitamin E. About 80% of the tocopherols of hempseed oil is
the alpha form. The vitamin E content of hempseed is comparatively high. Antioxidants
in hempseed oil are believed to stabilize the highly polyunsaturated oil, tending
to keep it from going rancid. Sterols in the seeds probably serve the same function,
and like the tocopherols are also desirable from a human health viewpoint.

Protein. Hemp seeds contain 25%30% protein, with a reasonably
complete amino acid spectrum. About two thirds of hempseed protein is edestin.
All eight amino acids essential in the human diet are present, as well as others.
Although the protein content is smaller than that of soybean, it is much higher
than in grains like wheat, rye, maize, oat, and barley. As noted above, the
oilcake remaining after oil is expressed from the seeds is a very nutritious
feed supplement for livestock, but it can also be used for production of a high-protein
flour.

Personal Care Products

In the 1990s, European firms introduced lines of hemp oil-based personal care
products, including soaps, shampoos, bubble baths, and perfumes. Hemp oil is
now marketed throughout the world in a range of body care products, including
creams, lotions, moisturizers, and lip balms. In Germany, a laundry detergent
manufactured entirely from hemp oil has been marketed. Hemp-based cosmetics
and personal care products account for about half of the world market for hemp
oil (de Guzman 2001).

One of the most significant developments for the North American hemp industry
was investment in hemp products by Anita and Gordon Roddick, founders of The
Body Shop, a well known international chain of hair and body care retailers.
This was a rather courageous and principled move that required overcoming American
legal obstacles related to THC content. The Body Shop now markets an impressive
array of hemp nutraceutical cosmetics (Fig. 39), and this has given the industry
considerable credibility. The Body Shop has reported gross sales of about a
billion dollars annually, and that about 4% of sales in 2000 were hemp products.

Fig. 39. Body care products offered by the Body Shop. (Chanvre
is French for hemp.)

Industrial Fluids

The vegetable oils have been classified by iodine value as drying
(120200), semi-drying (100120), and non-drying (80100), which
is determined by the degree of saturation of the fatty acids present (Raie et
al. 1995). Good coating materials prepared from vegetable oil depend on the
nature and number of double bonds present in the fatty acids. Linseed oil, a
drying oil, has a very high percentage of linolenic acid. Hempseed oil has been
classified as a semi-drying oil, like soybean oil, and is therefore more suited
to edible than industrial oil purposes. Nevertheless hemp oil has found applications
in the past in paints, varnishes, sealants, lubricants for machinery, and printing
inks. However, such industrial end uses are not presently feasible as the oil
is considered too expensive (de Guzman 2001). Larger production volumes and
lower prices may be possible, in which case hemp oil may find industrial uses
similar to those of linseed (flax), soybean, and sunflower oils, which are presently
used in paints, inks, solvents, binders, and in polymer plastics. Hemp shows
a remarkable range of variation in oil constituents, and selection for oilseed
cultivars with high content of valued industrial constituents is in progress.

MEDICINAL MARIJUANA

Marijuana has in fact been grown for medicinal research in North America by
both the Canadian (Fig. 40) and American governments, and this will likely continue.
The possibility of marijuana becoming a legal commercial crop in North America
is, to say the least, unlikely in the foreseeable future. Nevertheless the private
sector is currently producing medicinal marijuana in Europe and Canada, so the
following orientation to marijuana as a potential authorized crop is not merely
academic.

Fig. 40. A truckload of Canadian medicinal marijuana from a plantation
in Ottawa in 1971. More than a ton of marijuana was prepared for experimental
research (described in Small et al. 1975).

The objectivity of scientific evaluation of the medicinal value of marijuana
to date has been questioned. In the words of Hirst et al. (1998): The
...status of cannabis has made modern clinical research almost impossible. This
is primarily because of the legal, ethical and bureaucratic difficulties in
conducting trials with patients. Additionally, the general attitude towards
cannabis, in which it is seen only as a drug of abuse and addiction, has not
helped. In a recent editorial, the respected journal Nature (2001)
stated: Governments, including the US federal government, have until
recently refused to sanction the medical use of marijuana, and have also done
what they can to prevent its clinical testing. They have defended their inaction
by claiming that either step would signal to the public a softening of the so-called
war on drugs.... The pharmacology of cannabinoids is a valid field
of scientific investigation. Pharmacologists have the tools and the methodologies
to realize its considerable potential, provided the political climate permits
them to do so. Given these current demands for research on medicinal
marijuana, it will be necessary to produce crops of drug types of C. sativa.

Earliest reference to euphoric use of C. sativa appears to date to
China of 5 millennia ago, but it was in India over the last millennium that
drug consumption became more firmly entrenched than anywhere else in the world.
Not surprisingly, the most highly domesticated drug strains were selected in
India. While C. sativa has been used as a euphoriant in India, the Near
East, parts of Africa, and other Old World areas for thousands of years, such
use simply did not develop in temperate countries where hemp was raised. The
use of C. sativa as a recreational inebriant in sophisticated, largely
urban settings is substantially a 20th century phenomenon.

Cannabis drug preparations have been employed medicinally in folk medicine
since antiquity, and were extensively used in western medicine between the middle
of the 19th century and World War II, particularly as a substitute for opiates
(Mikuriya 1969). A bottle of commercial medicinal extract is shown in Fig. 41.
Medical use declined with the introduction of synthetic analgesics and sedatives,
and there is very limited authorized medical use today, but considerable unauthorized
use, including so-called compassion clubs dispensing marijuana to
gravely ill people, which has led to a momentous societal and scientific debate
regarding the wisdom of employing cannabis drugs medically, given the illicit
status. There is anecdotal evidence that cannabis drugs are useful for: alleviating
nausea, vomiting, and anorexia following radiation therapy and chemotherapy;
as an appetite stimulant for AIDS patients; for relieving the tremors of multiple
sclerosis and epilepsy; and for pain relief, glaucoma, asthma, and other ailments
[see Mechoulam and Hanus (1997) for an authoritative medical review, and Pate
(1995) for a guide to the medical literature]. To date, governmental authorities
in the US, on the advice of medical experts, have consistently rejected the
authorization of medical use of marijuana except in a handful of cases. However,
in the UK medicinal marijuana is presently being produced sufficient to supply
thousands of patients, and Canada recently authorized the cultivation of medicinal
marijuana for compassionate dispensation, as well as for a renewed effort at
medical evaluation.

Several of the cannabinoids are reputed to have medicinal potential: THC for
glaucoma, spasticity from spinal injury or multiple sclerosis, pain, inflammation,
insomnia, and asthma; CBD for some psychological problems. The Netherlands firm
HortaPharm developed strains of Cannabis rich in particular cannabinoids.
The British firm G.W. Pharmaceuticals acquired proprietary access to these for
medicinal purposes, and is developing medicinal marijuana. In the US, NIH (National
Institute of Health) has a program of research into medicinal marijuana, and
has supplied a handful of individuals for years with maintenance samples for
medical usage. The American Drug Enforcement Administration is hostile to the
medicinal use of Cannabis, and for decades research on medicinal properties
of Cannabis in the US has been in an extremely inhospitable climate,
except for projects and researchers concerned with curbing drug abuse. Synthetic
preparations of THCdronabinol (Marinol®) and nabilone (Cesamet®)are
permitted in some cases, but are expensive and widely considered to be less
effective than simply smoking preparations of marijuana. Relatively little material
needs to be cultivated for medicinal purposes (Small 1971), although security
considerations considerably inflate costs. The potential as a new crop
for medicinal cannabinoid uses is therefore limited. However, the added-value
potential in the form of proprietary drug derivatives and drug-delivery systems
is huge. The medicinal efficacy of Cannabis is extremely controversial,
and regrettably is often confounded with the issue of balancing harm and liberty
concerning the proscriptions against recreational use of marijuana. This paper
is principally concerned with the industrial uses of Cannabis. In this
context, the chief significance of medicinal Cannabis is that, like the
issue of recreational use, it has made it very difficult to rationally consider
the development of industrial hemp in North America for purposes that everyone
should agree are not harmful.

Key analyses of the medicinal use of marijuana are: Le Dain (1972), Health
Council of the Netherlands (1996), American Medical Association (1997), British
Medical Association (1997), National Institutes of Health (1997), World Health
Organization (1997), House of Lords (1998), and Joy et al. (1999).

MINOR USES

Biomass

It has been contended that hemp is notably superior to most crops in terms
of biomass production, but van der Werf (1994b) noted that the annual dry matter
yield of hemp (rarely approaching 20 t/ha) is not exceptional compared to maize,
beet, or potato. Nevertheless, hemp has been rated on a variety of criteria
as one of the best crops available to produce energy in Europe (Biewinga and
van der Bijl 1996). Hemp, especially the hurds, can be burned as is or processed
into charcoal, methanol, methane, or gasoline through pyrolysis (destructive
distillation). As with maize, hemp can also be used to create ethanol. However,
hemp for such biomass purposes is a doubtful venture in North America. Conversion
of hemp biomass into fuel or alcohol is impractical on this continent, where
there are abundant supplies of wood, and energy can be produced relatively cheaply
from a variety of sources. Mallik et al. (1990) studied the possibility of using
hemp for biogas (i.e. methane) production, and concluded that it
was unsuitable for this purpose. Pinfold Consulting (1998) concluded that while
there may be some potential for hemp biomass fuel near areas where hemp is cultivated,
a fuel ethanol industry is not expected to develop based on hemp.

Essential Oil

Essential (volatile) oil in hemp is quite different from hempseed oil. Examples
of commercial essential oil product products are shown in Fig. 42. The essential
oil is a mixture of volatile compounds, including monoterpenes, sesquiterpenes,
and other terpenoid-like compounds that are manufactured in the same epidermal
glands in which the resin of Cannabis is synthesized (Meier and Mediavilla
1998). Yields are very smallabout 10 L/ha (Mediavilla and Steinemann 1997),
so essential oil of C. sativa is expensive, and today is simply a novelty.
Essential oil of different strains varies considerably in odor, and this may
have economic importance in imparting a scent to cosmetics, shampoos, soaps,
creams, oils, perfumes, and foodstuffs. Switzerland has been a center for the
production of essential oil for the commercial market. Narcotic strains tend
to be more attractive in odor than fiber strains, and because they produce much
higher numbers of flowers than fiber strains, and the (female) floral parts
provide most of the essential oil, narcotic strains are naturally adapted to
essential oil production. Switzerland has permitted strains with higher THC
content to be grown than is allowed in other parts of the world, giving the
country an advantage with respect to the essential oil market. However, essential
oil in the marketplace has often been produced from low-THC Cannabis,
and the THC content of essential oil obtained by steam distillation can be quite
low, producing a product satisfying the needs for very low THC levels in food
and other commercial goods. The composition of extracted essential oil is quite
different from the volatiles released around the fresh plant (particularly limonene
and alpha-pinene), so that a pleasant odor of the living plant is not necessarily
indicative of a pleasant-smelling essential oil. Essential oil has been produced
in Canada by Gen-X Research Inc., Regina. The world market for hemp essential
oil is very limited at present, and probably also has limited growth potential.

Pesticide and Repellent Potential

McPartland (1997) reviewed research on the pesticide and repellent applications
of Cannabis. Dried plant parts and extracts of Cannabis have received
rather extensive usage for these purposes in the past, raising the possibility
that research could produce formulations of commercial value. This possibility
is currently hypothetical.

Non-Seed Use of Hemp as Livestock Feed

As noted above, hemp seed cake makes an excellent feed for animals. However,
feeding entire plants is another matter, because the leaves are covered with
the resin-producing glands. While deer, groundhogs, rabbits, and other mammals
will nibble on hemp plants, mammals generally do not choose to eat hemp. Jain
and Arora (1988) fed narcotic Cannabis refuse to cattle, and found that
the animals suffered variable degrees of depression and revealed incoordination
in movement. By contrast, Letniak et al. (2000) conducted an experimental
trial of hemp as silage. No significant differences were found between yield
of the hemp and of barley/oat silage fed to heifers, suggesting that fermenting
hemp plants reduces possible harmful constituents.

Hemp as an Agricultural Barrier

One of the most curious uses of hemp is as a fence to prevent pollen transfer
in commercial production of seeds. Isolation distances for ensuring that seeds
produced are pure are considerable for many plants, and often impractical. At
one point in the 1980s, the only permitted use of hemp in Germany was as a fence
or hedge to prevent plots of beets being used for seed production from being
contaminated by pollen from ruderal beets. The high and rather inpenetrable
hedge that hemp can produce was considered unsurpassed by any other species
for the purpose. As well, the sticky leaves of hemp were thought to trap pollen.
However, Saeglitz et al. (2000) demonstrated that the spread of beet pollen
is not effectively prevented by hemp hedges. Fiber (i.e. tall) cultivars of
hemp were also once used in Europe as wind-breaks, protecting vulnerable crops
against wind damage. Although hemp plants can lodge, on the whole very tall
hemp is remarkably resistant against wind.

Bioremediation

Preliminary work in Germany (noted in Karus and Leson 1994) suggested that
hemp could be grown on soils contaminated with heavy metals, while the fiber
remained virtually free of the metals. Kozlowski et al. (1995) observed that
hemp grew very well on copper-contaminated soil in Poland (although seeds absorbed
high levels of copper). Baraniecki (1997) found similar results. Mölleken
et al. (1997) studied effects of high concentration of salts of copper, chromium,
and zinc on hemp, and demonstrated that some hemp cultivars have potential application
to growth in contaminated soils. It would seem unwise to grow hemp as an oilseed
on contaminated soils, but such a habitat might be suitable for a fiber or biomass
crop. The possibility of using hemp for bioremediation deserves additional study.

Wildlife Uses

Hemp is plagued by bird predation, which take a heavy toll on seed production.
The seeds are well known to provide extremely nutritious food for both wild
birds and domestic fowl. Hunters and birdwatchers who discover wild patches
of hemp often keep this information secret, knowing that the area will be a
magnet for birds in the fall when seed maturation occurs. Increasingly in North
America, plants are being established to provide habitat and food for wildlife.
Hemp is not an aggressive weed, and certainly has great potential for being
used as a wildlife plant. Of course, current conditions forbid such usage in
North America.

Ornamental Forms

Hemp has at times in the past been grown simply for its ornamental value.
The short, strongly-branched cultivar Panorama (Fig. 43) bred by
Iván Bósca, the dean of the worlds living hemp breeders,
was commercialized in Hungary in the 1980s, and has been said to be the only
ornamental hemp cultivar available. It has had limited success, of course, because
there are very few circumstances that permit private gardeners can grow Cannabis
as an ornamental today. By contrast, beautiful ornamental cultivars of opium
poppy are widely cultivated in home gardens across North America, despite their
absolute illegality and the potentially draconian penalties that could be imposed.
Doubtless in the unlikely event that it became possible, many would grow hemp
as an ornamental.

AGRONOMY

The following sketch of hemp cultivation is insufficient to address all of
the practical problems that are encountered by hemp growers. Bócsa and
Karus (1998) is the best overall presentation of hemp growing available in English.
The reader is warned that this book, as well as almost all of the literature
on hemp, is very much more concerned with fiber production than oilseed production.
McPartland et al. (2000) is the best presentation available on diseases and
pests, which fortunately under most circumstances do limited damage. The resource
list presented below should be consulted by those wishing to learn about hemp
production. Provincial agronomists in Canada now have experience with hemp,
and can make local recommendations. Particularly good web documents are: for
Ontario (OMAFRA Hemp Series, several documents): www.gov.on.ca/OMAFRA/english/crops/hort/hemp.html);
for Manitoba (several documents): www.gov.mb.ca/agriculture/crops/hemp/bko01s00.html;
for British Columbia: (BC Ministry of Agriculture and Foods Fact Sheet on Industrial
Hemp, prepared by A. Oliver and H. Joynt): www.agf.gov.bc.ca/croplive/plant/horticult/specialty/specialty.htm

In the US, extension publications produced up to the end of World War II are
still useful, albeit outdated (Robinson 1935; Wilsie et al. 1942; Hackleman
and Domingo 1943; Wilsie et al. 1944).

Hemp does best on a loose, well-aerated loam soil with high fertility and
abundant organic matter. Well-drained clay soils can be used, but poorly-drained
clay soils are very inappropriate because of their susceptibility to compaction,
which is not tolerated. Young plants are sensitive to wet or flooded soils,
so that hemp must have porous, friable, well-drained soils. Sandy soils will
grow good hemp, provided that adequate irrigation and fertilization are provided,
but doing so generally makes production uneconomical. Seedbed preparation requires
considerable effort. Fall plowing is recommended, followed by careful preparation
of a seedbed in the spring. The seedbed should be fine, level, and firm. Seed
is best planted at 23 cm (twice as deep will be tolerated). Although the
seedlings will germinate and survive at temperatures just above freezing, soil
temperatures of 8°10°C are preferable. Generally hemp should be
planted after danger of hard freezes, and slightly before the planting date
of maize. Good soil moisture is necessary for seed germination, and plenty of
rainfall is needed for good growth, especially during the first 6 weeks. Seeding
rate is specific to each variety, and this information should be sought from
the supplier. Fiber strains are typically sown at a minimum rate of 250 seeds
per m2 (approximately 45 kg/ha), and up to three times this density is sometimes
recommended. In western Europe, seeding rates range from 6070 kg/ha for
fiber cultivars. Recommendations for seeding rates for grain production vary
widely, from 1045 kg/ha. Densities for seed production for tall, European,
dual-purpose cultivars are less than for short oilseed cultivars. Low plant
densities, as commonly found in growing tall European cultivars for seed, may
not suppress weed growth adequately, and under these circumstances resort to
herbicides may pose a problem for those wishing to grow hempseed organically.
Hemp requires about the same fertility as a high-yielding crop of wheat. Industrial
hemp grows well in areas that corn produces high yields. Growing hemp may require
addition of up to 110 kg/ha of nitrogen, and 4090 kg/ha of potash. Hemp
particularly requires good nitrogen fertilization, more so for seed production
than fiber. Adding nitrogen when it is not necessary is deleterious to fiber
production, so that knowledge of the fertility of soils being used is very important.
Organic matter is preferably over 3.5%, phosphorus should be medium to high
(>40 ppm), potassium should be medium to high (>250 ppm), sulfur good
(>5,000 ppm), and calcium not in excess (<6,000 ppm).

Finding cultivars suited to local conditions is a key to success. Hemp prefers
warm growing conditions, and the best European fiber strains are photoperiodically
adapted to flowering in southern Europe, which provides seasons of at least
4 months for fiber, and 5.5 months for seed production. Asian land races are
similarly adapted to long seasons. In Canada, many of the available cultivars
flower too late in the season for fiber production, and the same may be predicted
for the northern US. Fiber production should also be governed by availability
of moisture throughout the season, and the need for high humidity in the late
summer and fall for retting, so that large areas of the interior and west of
North America are not adapted to growing fiber hemp. The US Corn Belt has traditionally
been considered to be best for fiber hemp. There are very few cultivars dedicated
to oilseed production (such as Finola and Anka) or that
at least are known to produce good oilseed crops (such as Fasamo
and Uniko-B). Oilseed production was a specialty of the USSR, and
there is some likelihood that northern regions of North America may find short-season,
short-stature oilseed cultivars ideal.

Although hemp can be successfully grown continuously for several years on
the same land, rotation with other crops is desirable. A 3- or preferably 4-year
rotation may involve cereals, clover or alfalfa for green manure, maize, and
hemp. In Ontario it has been recommended that hemp not follow canola, edible
beans, soybeans or sunflowers. However, according to Bócsa and Karus
(1998), it matters little what crops are grown prior to hemp.

For a fiber crop, hemp is cut in the early flowering stage or while pollen
is being shed, well before seeds are set. Tall European cultivars (greater than
2 m) have mostly been grown in Canada to date, and most of these are photoperiodically
adapted to mature late in the season (often too late). Small crops have been
harvested with sickle-bar mowers and hay swathers, but plugging of equipment
is a constant problem. Hemp fibers tend to wrap around combine belts, bearings,
indeed any moving part, and have resulted in large costs of combine repairs
(estimated at $10.00/ha). Slower operation of conventional combines has been
recommended (0.62 ha/hour). Large crops may require European specialized
equipment, but experience in North America with crops grown mainly for fiber
is limited. The Dutch company HempFlax has developed or adapted several kinds
of specialized harvesting equipment (Fig. 44, 45).

Fig. 45. A hemp harvester operated by HempFlax (Netherlands), with
a wide mowing head capable of cutting 3 m long stems into 0.6 m pieces,
at a capacity of 3 ha/hour. (Courtesy of HempFlax, Oude Pekela, The Netherlands.)

Retting is generally done in the field (Fig. 46, 47). This typically requires
weeks. The windrows should be turned once or twice. If not turned, the stems
close to the ground will remain green while the top ones are retted and turn
brown. When the stalks have become sufficiently retted requires experiencethe
fibers should have turned golden or grayish in color, and should separate easily
from the interior wood. Baling can be done with any kind of baler (Fig. 48).
Stalks should have less than 15% moisture when baled, and should be allowed
to dry to about 10% in storage. Bales must be stored indoors. Retted stalks
are loosely held together, and for highest quality fiber applications need to
be decorticated, scutched, hackled, and combed to remove the remaining pieces
of stalks, broken fibers, and extraneous material. The equipment for this is
rare in North America, and consequently use of domestically-produced fiber for
high quality textile applications is extremely limited. However, as described
above relatively crude fiber preparations also have applications.

Harvesting tall varieties for grain is difficult. In France, the principal
grower of dual-purpose varieties, the grain is taken off the field first, leaving
most of the stalks for later harvest (Fig. 49). Putting tall whole plants through
a conventional combine results in the straw winding around moving parts, and
the fibers working into bearings, causing breakdown, fires, high maintenance,
and frustration. Following the French example of raising the cutting blade to
harvest the grain is advisable. Growing short varieties dedicated to grain production
eliminates many of the above problems, and since the profitability of hemp straw
is limited at present, seems preferable. Grain growers should be aware that
flocks of voracious birds are a considerable source of damage to hempseed, particularly
in small plantations.

ECOLOGICAL FRIENDLINESS OF HEMP

Although the environmental and biodiversity benefits of growing hemp have
been greatly exaggerated in the popular press, C. sativa is nevertheless
exceptionally suitable for organic agriculture, and is remarkably less ecotoxic
in comparison to most other crops (Montford and Small 1999b). Figure 50 presents
a comparison of the ecological friendliness of Cannabis crops (fiber,
oilseed, and narcotics) and 21 of the worlds major crops, based on 26
criteria used by Montford and Small (1999a) to compare the ecological friendliness
of crops.

Fig. 50. A crude comparison of the biodiversity friendliness of selected
major crops and three Cannabis sativa crops (fiber, oilseed, drug) based
on 26 criteria (after Montford and Small 1999a).

The most widespread claim for environmental friendliness of hemp is that it
has the potential to save trees that otherwise would be harvested for production
of lumber and pulp. Earlier, the limitations of hemp as a pulp substitute were
examined. With respect to wood products, several factors appear to favor increased
use of wood substitutes, especially agricultural fibers such as hemp. Deforestation,
particularly the destruction of old growth forests, and the worlds decreasing
supply of wild timber resources are today major ecological concerns. Agroforestry
using tree species is one useful response, but nevertheless sacrifices wild
lands and biodiversity, and is less preferable than sustainable wildland forestry.
The use of agricultural residues (e.g. straw bales in house construction) is
an especially environmentally friendly solution to sparing trees, but material
limitations restrict use. Another chief advantage of several annual fiber crops
over forestry crops is relative productivity, annual fiber crops sometimes producing
of the order of four times as much per unit of land. Still another important
advantage is the precise control over production quantities and schedule that
is possible with annual crops. In many parts of the world, tree crops are simply
not a viable alternative. By the turn of the century 3 billion people
may live in areas where wood is cut faster than it grows or where fuelwood is
extremely scarce (World Commission on Environment and Development
1987). Since mid-century, lumber use has tripled, paper use has increased
six-fold, and firewood use has soared as Third World populations have multiplied
(Brown et al. 1998). Insofar as hemp reduces the need to harvest trees for building
materials or other products, its use as a wood substitute will tend to contribute
to preserving biodiversity. Hemp may also enhance forestry management by responding
to short-term fiber demand while trees reach their ideal maturation. In developing
countries where fuelwood is becoming increasingly scarce and food security is
a concern, the introduction of a dual-purpose crop such as hemp to meet food,
shelter, and fuel needs may contribute significantly to preserving biodiversity.

The most valid claims to environmental friendliness of hemp are with respect
to agricultural biocides (pesticides, fungicides, herbicides). Cannabis sativa
is known to be exceptionally resistant to pests (Fig. 51), although, the degree
of immunity to attacking organisms has been greatly exaggerated, with several
insects and fungi specializing on hemp. Despite this, use of pesticides and
fungicides on hemp is usually unnecessary, although introduction of hemp to
regions should be expected to generate local problems. Cannabis sativa
is also relatively resistant to weeds, and so usually requires relatively little
herbicide. Fields intended for hemp use are still frequently normally cleared
of weeds using herbicides, but so long as hemp is thickly seeded (as is always
done when hemp is grown for fiber), the rapidly developing young plants normally
shade out competing weeds.

Fig. 51. Grasshopper on hemp. Most insects cause only limited damage
to hemp, and substantial insect damage is uncommon, so the use of insecticides
is very rarely required.

BREEDING HEMP FOR NORTH AMERICA

The basic commercial options for growing hemp in North America is as a fiber
plant, an oilseed crop, or for dual harvest for both seeds and fiber. Judged
on experience in Canada to date, the industry is inclined to specialize on either
fiber or grain, but not both. Hemp in our opinion is particularly suited to
be developed as an oilseed crop in North America. The first and foremost breeding
goal is to decrease the price of hempseed by creating more productive cultivars.
While the breeding of hemp fiber cultivars has proceeded to the point that only
slight improvements can be expected in productivity in the future, the genetic
potential of hemp as an oilseed has scarcely been addressed. From the point
of view of world markets, concentrating on oilseed hemp makes sense, because
Europe has shown only limited interest to date in developing oilseed hemp, whereas
a tradition of concentrating on profitable oilseed products is already well
established in the US and Canada. Further, Chinas supremacy in the production
of high-quality hemp textiles at low prices will be very difficult to match,
while domestic production of oilseeds can be carried out using technology that
is already available. The present productivity of oilseed hempabout 1
t/ha under good conditions, and occasional reports of 1.5 to 2 t/ha, is not
yet sufficient for the crop to become competitive with North Americas
major oilseeds. We suggest that an average productivity of 2 t/ha will be necessary
to transform hempseed into a major oilseed, and that this breeding goal is achievable.
At present, losses of 30% of the seed yields are not uncommon, so that improvements
in harvesting technology should also contribute to higher yields. Hemp food
products cannot escape their niche market status until the price of hempseed
rivals that of other oilseeds, particularly rapeseed, flax, and sunflower. Most
hemp breeding that has been conducted to date has been for fiber characteristics,
so that there should be considerable improvement possible. The second breeding
goal is for larger seeds, as these are more easily shelled. Third is breeding
for specific seed components. Notable are the health-promoting gamma-linolenic
acid; improving the amino acid spectrum of the protein; and increasing the antioxidant
level, which would not only have health benefits but could increase the shelf
life of hemp oil and foods.

Germplasm Resources

Germplasm for the improvement of hemp is vital for the future of the industry
in North America. However, there are no publicly available germplasm banks housing
C. sativa in North America. The hundreds of seed collections acquired
for Smalls studies (reviewed in Small 1979) were destroyed in 1980 because
Canadian government policy at that time envisioned no possibility that hemp
would ever be developed as a legitimate crop. An inquiry regarding the 56 United
States Department of Agriculture hemp germplasm collections supplied to and
grown by Small and Beckstead (1973) resulted in the reply that there are no
remaining hemp collections in USDA germplasm holdings, and indeed that were
such to be found they would have to be destroyed. While hemp has been and still
is cultivated in Asia and South America, it is basically in Europe that germplasm
banks have made efforts to preserve hemp seeds. The Vavilov Institute of Plant
Research in St. Petersburg, Russia has by far the largest germplasm collection
of hemp of any public gene bank, with about 500 collections. Detailed information
on the majority of hemp accessions of the Vavilov Institute can be found in
Anon. (1975). Budgetary problems in Russia have endangered the survival of this
invaluable collection, and every effort needs to be made to find new funding
to preserve it. Maintenance and seed generation issues for the Vavilov hemp
germplasm collection are discussed in a number of articles in the Journal of
the International Hemp Association (Clarke 1998b; Lemeshev et al. 1993, 1994).
The Gatersleben gene bank of Germany, the 2nd largest public gene bank in Europe,
has a much smaller Cannabis collection, with less than 40 accessions
(detailed information on the hemp accessions of the Gatersleben gene bank are
available at fox-serv.ipk-gatersleben.de/). Because hemp is regaining its ancient
status as an important crop, a number of private germplasm collections have
been assembled for the breeding of cultivars as commercial ventures (de Meijer
and van Soest 1992; de Meijer 1998), and of course these are available only
on a restricted basis, if at all.

The most pressing need of the hemp industry in North America is for the breeding
of more productive oilseed cultivars. At present, mainly European cultivars
are available, of which very few are suitable for specialized oilseed production.
More importantly, hempseed oil is not competitive, except in the novelty niche
market, with the popular food oils. As argued above, to be competitive, hemp
should produce approximately 2 t/ha; at present 1 t/ha is considered average
to good production. Doubling the productive capacity of a conventional crop
would normally be considered impossible, but it needs to be understood just
how little hemp has been developed as an oilseed. There may not even be extant
land races of the kind of hemp oilseed strains that were once grown in Russia,
so that except for a very few very recent oilseed cultivars, there has been
virtually no breeding of oilseed hemp. Contrarily, hemp has been selected for
fiber to the point that some breeders consider its productivity in this respect
has already been maximized. Fiber strains have been selected for low seed production,
so that most hemp germplasm has certainly not been selected for oilseed characteristics.
By contrast, drug varieties have been selected for very high yield of flowers,
and accordingly produce very high yield of seeds. Drug varieties have been observed
to produce more than a kilogram of seed per plant, so that a target yield of
several tonnes per hectare is conceivable (Watson and Clarke 1997). Of course,
the high THC in drug cultivars makes these a difficult source of germplasm.
However, wild plants of C. sativa have naturally undergone selection
for high seed productivity, and are a particularly important potential source
of breeding germplasm.

Wild North American hemp is derived mostly from escaped European cultivated
hemp imported in past centuries, perhaps especially from a revival of cultivation
during World War II. Wild Canadian hemp is concentrated along the St. Lawrence
and lower Great Lakes, where considerable cultivation occurred in the 1800s.
In the US, wild hemp is best established in the American Midwest and Northeast,
where hemp was grown historically in large amounts. Decades of eradication have
exterminated many of the naturalized populations in North America. In the US,
wild plants are rather contemptuously called ditch weed by law enforcement
personnel. However, the attempts to destroy the wild populations are short-sighted,
because they are a natural genetic reservoir, mostly low in THC. Wild North
American plants have undergone many generations of natural adaptation to local
conditions of climate, soil and pests, and accordingly it is safe to conclude
that they harbor genes that are invaluable for the improvement of hemp cultivars.
We have encountered exceptionally vigorous wild Canadian plants (Fig. 52), and
grown wild plants from Europe (Fig. 53) which could prove valuable. Indeed,
studies are in progress in Ontario to evaluate the agronomic usefulness of wild
North American hemp. Nevertheless, present policies in North America require
the eradication of wild hemp wherever encountered. In Europe and Asia, there
is little concern about wild hemp, which remains a valuable resource.

Fig. 53. A wild female hemp plant grown in southern
Ontario [accession #16 from Georgia (formerly USSR), reported in Small and
Marcus (2000)]. Such highly-branched plants can produce very large quantities
of seeds, and may be useful for breeding.

HARD LESSONS FOR FARMERS

It is clear that there is a culture of idealistic believers in hemp in North
America, and that there is great determination to establish the industry. As
history has demonstrated, unbridled enthusiasm for largely untested new crops
touted as gold mines sometimes leads to disaster. The attempt to raise silk
in the US is probably the most egregious example. In 1826 a Congressional report
that recommended the preparation of a practical manual on the industry resulted
in a contagious desire to plant mulberries for silk production, with the eventual
collapse of the industry, the loss of fortunes, and a legacy of Mulberry
Streets in the US (Chapter 2, Bailey 1898). In the early 1980s in Minnesota,
Jerusalem artichoke was touted as a fuel, a feed, a food, and a sugar crop.
Unfortunately there was no market for the new wonder crop and hundreds
of farmers lost about $20 million (Paarlberg 1990). The level of hype
associated with industrial hemp is far more than has been observed before for
other new crops (Pinfold Consulting 1998). Probably more so than any plant in
living memory, hemp attracts people to attempt its cultivation without first
acquiring a realistic appreciation of the possible pitfalls. American presidents
George Washington and Thomas Jefferson encouraged the cultivation of hemp, but
both lost money trying to grow it. Sadly in Canada in 1999 numerous farmers
contracted to grow half of Canadas crop area for hemp for the American-based
Consolidated Growers and Processors, and with the collapse of the firm were
left holding very large amounts of unmarketable grain and baled hemp straw.
This has represented a most untimely setback for a fledgling industry, but at
least has had a sobering effect on investing in hemp. In this section we emphasize
why producers should exercise caution before getting into hemp.

In Europe and Asia, hemp farming has been conducted for millennia. Although
most countries ceased growing hemp after the second word war, some didnt,
including France, China, Russia, and Hungary, so that essential knowledge of
how to grow and process hemp was maintained. When commercial hemp cultivation
resumed in Canada in 1997, many farmers undertook to grow the crop without appreciating
its suitability for their situation, or for the hazards of an undeveloped market.
Hemp was often grown on farms with marginal incomes in the hopes that it was
a savior from a downward financial spiral. The myth that hemp is a wonder crop
that can be grown on any soil led some to cultivate on soils with a history
of producing poor crops; of course, a poor crop was the result.

Market considerations also heavily determine the wisdom of investing in hemp.
Growing hemp unfortunately has a magnetic attraction to many, so there is danger
of overproduction. A marketing board could be useful to prevent unrestrained
competition and price fluctuations, but is difficult to establish when the industry
is still very small. As noted above, unwise investment in Canada produced a
glut of seeds that resulted in price dumping and unprofitable levels for the
majority. Cultural and production costs of hemp have been said to be comparable
to those for corn, and while the truth of this remains to be confirmed, the
legislative burden that accompanies hemp puts the crop at a unique disadvantage.
Among the problems that Canadian farmers have faced are the challenge of government
licensing (some delays, and a large learning curve), very expensive and sometime
poor seed (farmers are not allowed to generate their own seed), teenagers raiding
fields in the mistaken belief that marijuana is being grown, and great difficulties
in exportation because of the necessity of convincing authorities that hemp
is not a narcotic. Unless the producer participates in sharing of value-added
income, large profits are unlikely. The industry widely recognizes that value
added to the crop is the chief potential source of profit, as indeed for most
other crops.

THE POLITICS OF CANNABIS WITH PARTICULAR REFERENCE TO THE US

Cannabis has long had an image problem, because of the extremely widespread
use of narcotic cultivars as illegal intoxicants. The US Drug Enforcement
Administration has the mandate of eliminating illicit and wild marijuana, which
it does very well (Fig. 5456). Those interested in establishing and developing
legitimate industries based on fiber and oilseed applications have had to struggle
against considerable opposition from many in the political and law enforcement
arenas. The United States National Institute on Drug Abuse (NIDA) information
web site on marijuana, which reflects a negative view of cannabis, is at www.nida.nih.gov/DrugPages/Marijuana.html,
and reflects several basic fears: (1) growing Cannabis plants makes law
enforcement more difficult, because of the need to ensure that all plants cultivated
are legitimate; (2) utilization of legitimate Cannabis products makes
it much more difficult to maintain the image of the illegitimate products as
dangerous; (3) many in the movements backing development of hemp are doing so
as a subterfuge to promote legalization of recreational use of marijuana; and
(4) THC (and perhaps other constituents) in Cannabis are so harmful that
their presence in any amount in any material (food, medicine or even fiber product)
represents a health hazard that is best dealt with by a total proscription.

Fig. 54. The war on drugs: helicopter spraying of Paraquat
herbicide on field of marijuana. (Courtesy US Drug Enforcement Administration.)

Ten years ago hemp cultivation was illegal in Germany, England, Canada, Australia,
and other countries. Essential to overcoming governmental reluctance in each
country was the presentation of an image that was business-oriented, and conservative.
The merits of environmentalism have acquired some political support, but unless
there is a reasonable possibility that hemp cultivation is perceived as potentially
economically viable, there is limited prospect of having anti-hemp laws changed.
Strong support from business and farm groups is indispensable; support from
pro-marijuana interests and what are perceived of as fringe groups is generally
counterproductive. It is a combination of prospective economic benefit coupled
with assurance that hemp cultivation will not detrimentally affect the enforcement
of marijuana legislation that has led most industrially advanced countries to
reverse prohibitions against growing hemp. Should the US permit commercial hemp
cultivation to resume, it will likely be for the same reasons.

The US Office of National Drug control Policy issued a statement on industrial
hemp in 1997 (www.whitehousedrugpolicy.gov/policy/hemp%5Fold.html) which included
the following: Our primary concern about the legalization of the cultivation
of industrial hemp (Cannabis sativa) is the message it would send to
the public at large, especially to our youth at a time when adolescent drug
use is rising rapidly... The second major concern is that legalizing hemp production
may mean the de facto legalization of marijuana cultivation. Industrial hemp
and marijuana are the product of the same plant, Cannabis sativa... Supporters
of the hemp legalization effort claim hemp cultivation could be profitable for
US farmers. However, according to the USDA and the US Department of Commerce,
the profitability of industrial hemp is highly uncertain and probably unlikely.
Hemp is a novelty product with limited sustainable development value even in
a novelty market... For every proposed use of industrial hemp, there already
exists an available product, or raw material, which is cheaper to manufacture
and provides better market results.... Countries with low labor costs such as
the Philippines and China have a competitive advantage over any US hemp producer.

Recent European Commission proposals to change its subsidy regime for hemp
contained the following negative evaluation of hemp seed: The use of
hemp seed ... would, however, even in the absence of THC, contribute towards
making the narcotic use of cannabis acceptable... In this light, subsidy will
be denied producers who are growing grain for use in human nutrition and cosmetics.

A USDA analysis of hemp, Industrial hemp in the United States: Status
and market potential, was issued in 2000, and is available at www.ers.usda.gov/publications/ages001e/index.htm.
This is anonymously-authored, therefore presumably represents a corporate or
official evaluation. The conclusion was that US markets
for hemp fiber (specialty textiles, paper, and composites) and seed (in food
or crushed for oil) are, and will likely remain, small, thin markets. Uncertainty
about longrun demand for hemp products and the potential for oversupply discounts
the prospects for hemp as an economically viable alternative crop for American
farmers. Noting the oversupply of hempseeds associated with Canadas
12,000 ha in 1999, the report concluded that the long term demand for hemp products
is uncertain, and predicts that the hemp market in the US will likely remain
small and limited. With respect to textiles, the report noted the lack of a
thriving textile flax (linen) US industry (despite lack of legal barriers),
so that it would seem unlikely that hemp could achieve a better market status.
With respect to hemp oil, the report noted that hemp oil in food markets is
limited by its short shelf life, the fact that it can not be used for frying,
and the lack of US Food and Drug Administration approval as GRAS (generally
recognized as safe). Moreover, summarizing four state analyses of hemp
production (McNulty 1995, Ehrensing 1998, Kraenzel et al. 1998, Thompson et
al. 1998), profitability seemed doubtful.

Without arguing the merits of the above contentions, we point out that the
legitimate use of hemp for non-intoxicant purposes has been inhibited by the
continuing ferocious war against drug abuse. In this atmosphere, objective analysis
has often been lacking. Unfortunately both proponents and opponents have tended
to engage in exaggeration. Increasingly, however, the world is testing the potential
of hemp in the field and marketplace, which surely must be the ultimate arbiters.
De Guzman (2001), noting the pessimistic USDA report, observed that Nevertheless,
others point to the potential of [the] market. Hemp products have a growing
niche market of their own, and the market will remain healthy and be well supported
with many competing brands.

A wide variety of hemp clothing, footwear, and food products are now available
in North America. Some American manufacturers and distributors have chosen to
exploit the association of hemp products with marijuana in their advertising.
Such marketing is unfortunate, sending the message that some in the industry
are indifferent to the negative image that this generates in the minds of much
of the potential consuming public. Admittedly, such advertising works. But marketing
based on the healthful and tasteful properties of hemp food products, the durable
nature of hemp textiles, and the environmental advantages of the crop has proven
to be widely acceptable, and is likely to promote the long term development
of hemp industries.

Will hemp commercial cultivation resume in the US in the foreseeable future?
This is difficult to judge, but the following considerations suggest this might
occur: (1) increasing awareness of the differences between industrial hemp and
marijuana; (2) growing appreciation of the environmental benefits of hemp cultivation;
(3) continuing demonstration of successful hemp cultivation and development
in most of the remaining western world; all the G8 countries, except the US,
produce and export industrial hemp; and (4) increasing pressure on state and
federal governments to permit hemp cultivation by farmers, particularly wheat,
corn, and tobacco farmers in desperate need of substitute crops, but also for
rotation crops to break pest and disease cycles.

More than a century ago, an expert on hemp concluded his manual on hemp-growing
in the US by stating There is no question that when the inventive genius,
comprehension and energies of the American people become interested, another
grand source of profitable employment and prosperity will be established
(Boyce 1900).

MARKET DEVELOPMENT

Individual entrepreneurs, and indeed whole industries, as a matter of economic
survival need to adopt a clear investment policy with respect to whether their
market is to be output-driven or demand-led. From the individual producers
perspective, the old adage find your market before you plant your seed
remains sound advice.

In the mid 1990s, the EU provided subsidization for hemp cultivation of ca.
$1,050/ha. This support was instrumental in developing a hemp industry in western
Europe. However, no comparable support is available in North America, and indeed
those contemplating entering into hemp cultivation are faced with extraordinary
costs and/or requirements in connection with licensing, security, THC analysis,
and record keeping. Those involved in value-added processing and distribution
are also faced with legal uncertainties and the regular threat of idiosyncratic,
indeed irrational actions of various governments. Simply displaying a C.
sativa leaf on advertising has led to the threat of criminal charges in
the last decade in several G8 countries. Attempting to export or import hemp
products among countries is presently a most uncertain activity.

It often takes 10 to 15 years for the industry associated with a new agricultural
crop to mature. While it is true that foreign imports have been the basis for
hemp products in North America for at least a decade, North American production
is only 4 years of age in Canada, and farming of hemp in the US has not even
begun. Viewed from this perspective, the hemp industry in North America is still
very much in its infancy. Varieties of hemp specifically suited to given products
and regions have only started to be developed in North America. There is considerable
uncertainty regarding yields, costs of production, harvesting and processing
equipment, product characteristics, foreign competition, governmental support,
and the vagaries of the regulatory environment. Hemp is not presently a standard
crop, and is likely to continue experiencing the risks inherent in a small niche
market for some time. Hemp is currently a most uncertain crop, but has such
a diversity of possible uses, is being promoted by extremely enthusiastic market
developers, and attracts so much attention that it is likely to carve out a
much larger share of the North American marketplace than its detractors are
willing to concede.

Given the uncertainties and handicaps associated with hemp, it is fortunate
that there are compensating factors. As noted, as a crop hemp offers some real
environmental advantages, particularly with regard to the limited needs for
herbicides and pesticides. Hemp is therefore pre-adapted to organic agriculture,
and accordingly to the growing market for products associated with environmentally-friendly,
sustainable production. Hemp products are an advertisers dream, lending
themselves to hyperbole (healthiest salad oil in the world, toughest
jeans on the market). While the narcotics image of C. sativa is
often disadvantageous, advertisers who choose to play up this association do
so knowing that it will attract a segment of the consuming population. In general,
the novelty of hemp means that many consumers are willing to pay a premium price.
It might also be said that those who have entered the hemp industry have tended
to be very highly motivated, resourceful, and industrious, qualities that have
been needed in the face of rather formidable obstacles to progress.

INFORMATION RESOURCES

Organizations

North American Industrial Hemp Council Inc.: www.naihc.org

Hemp Industries Association: www.thehia.org

International Hemp Association: mojo.calyx.net/~olsen/HEMP/IHA/

Hemp Food Association: hempfood.com/

Ontario Hemp Alliance: www.ontariohempalliance.org

International Association for Cannabis as Medicine: www.acmed.org/english/main.htm

Web

The Hemp Commerce & Farming Report: www.hempreport.com

Industrial hemp information network: www.hemptech.com

Journals

Journal of the International Hemp Association. Vol. 1 (1994)Vol.
6 (1999). (Vols. 15 and part of Vol. 6 available online at mojo.calyx.net/~olsen/HEMP/IHA/).
Superseded by Journal of Industrial Hemp.

REFERENCES

American Medical Association. 1997. Report 10 of the Council on Scientific
Affairs (I-97) to the American Medical Association House of Delegates. Subject:
Medical Marijuana. American Medical Association, Chicago. www.ama-assn.org/ama/pub/article/2036-4299.html

Health Council of the Netherlands. 1996. Marihuana as medicine. Health
Council of the Netherlands, Standing Committee on Medicine, Publication no.
1996/21. Rijswikj, the Netherlands. (summary: www.sarnia.com/groups/antidrug/mjmeds/nthrlnds.html)